Farm Futures: September Call-up Candidates

Predicting when a player like Ronald Acuna or Gleyber Torres will be called up to make their big-league debut during the first five months of the season is an abstract activity that requires instincts, experience and a good feel for how a player's skills will play at the highest level. However, predicting which prospects and former prospects will be recalled when the calendar turns to September and rosters expand is more science than art.

In 90 percent of cases, a player's standing on the 40-man roster will open or shut the door on any conversation about a September callup. Very rarely does it make sense to add a player to the 40-man roster after Sept. 1. This is especially true of teams that are not contending.

There are three instances when a team will add a prospect to the 40-man roster in September. The first instance is when a contending team has a need and the only internal replacement is a prospect who is not on the 40-man roster. This is pretty rare, but it happened last year with Alex Verdugo and Walker Buehler joining the Dodgers for the final month. The second scenario is when a team sees value in getting a look at a player against big-league pitching over the final month, even if they expect that player to head back to the minors at the start of the next season. For instance, Willie Calhoun was promoted to the big leagues a little over a month after being traded to Texas last year, as his new team wanted to evaluate his bat and glove at the highest level. The third scenario is when a player needs to be added to the 40-man roster in the upcoming offseason in order to be protected from the Rule 5 draft and the team is comfortable clearing a 40-man roster spot for that player prior to the offseason. This was the case when the Braves selected Luiz Gohara's contract last September, and Gohara went on to strike out 31 in 29.1 innings over five big-league starts in the season's final month.

What follows is an attempt to highlight the notable players who could be added to big-league rosters when rosters expand next month. They are sorted by the position they qualify for in fantasy, and within those positions they are ranked in order of how appealing they should be for fantasy owners looking to receive a boost over the final month of the season. Every player listed under a position is currently on their team's 40-man roster. The last two sections cover the players who will need to be added to their team's 40-man roster during the offseason for Rule 5 protection and those who are not on the 40-man roster and don't need to be added in the offseason.

CATCHER

Francisco Mejia (Padres): He will presumably be up in early September when El Paso's season is over, but Austin Hedges has a .932 OPS in the second half, so I don't see Mejia getting more than a start or two per week over the final 3-4 weeks.

Tom Murphy (Rockies): Like with Mejia, we can't expect Murphy to get more than a start or two per week in September. He may be a better bet for power over that brief span, but there is mounting evidence that he will never hit for a high enough average in the majors to make up for his middling defense.

Carson Kelly (Cardinals): Kelly has slashed just .150/.216/.187 in 118 MLB plate appearances, but he has once again been a well above league average hitter (113 wRC+) in the Pacific Coast League, and catchers often take a while to hit their stride at the plate in the majors. However, as with the rest of the catchers mentioned here, playing time will be hard to come by.

FIRST BASE/DH

Daniel Vogelbach (Mariners): As a 25-year-old designated hitter who has struggled against big-league pitching (.192 AVG, 31.7 percent K rate) and is blocked by Nelson Cruz, it's easy and probably warranted in many formats to forget about Vogelbach. He has turned into the definition of a Quad-A bat, hitting .302/.441/.561 with 67 walks and 47 strikeouts in 333 plate appearances in the PCL this year. They are still deploying him at first base in the minors, so perhaps he can get some starts there for the Mariners down the stretch.

AJ Reed (Astros): Speaking of Quad-A bats, Reed is also 25 and has been less productive than Vogelbach this year in the PCL, hitting .266/.360/.524 with 24 homers and a 98:59 K:BB in 461 plate appearances. The Astros and their players can talk all they want about how great of a hitter Yuli Gurriel is, but he's 34 and owns a 93 wRC+ as a first baseman on a team with World Series aspirations. Reed may not be the answer, but there appears to be an opening if someone wants to take advantage of it.

Rowdy Tellez (Blue Jays): While Tellez doesn't have big-league failure in his history like Vogelbach and Reed, he also doesn't have as much success to point to at Triple-A. He doesn't get to play in the hitter-friendly PCL, but it's still not a great sign that he has just 17 home runs in 221 career games at Triple-A.

Dominic Smith (Mets): Smith peaked as a prospect in 2017 at Triple-A, and while his big-league numbers in 257 plate appearances aren't promising (.193/.249/.374), his struggles in a return trip to the PCL (.256/.333/.392) are even more concerning. He is still just 23 and his team context is more appealing than the rest of these Triple-A first basemen, but he is pretty clearly the worst hitter of the bunch.

SECOND BASE

Garrett Hampson (Rockies): Hampson, who figures to be optioned back to Triple-A in a couple days, will be one of the best fantasy prospects to join a big-league roster in September, but playing time could be sparse. DJ LeMahieu doesn't deserve everyday at-bats, but sometimes in Colorado, deserve's got nothing to do with it. That said, with Hampson capable of playing second, shortstop and center field, he could get two or three starts in his first week back, and then if he hits, maybe that turns into four starts per week over the final couple weeks of the season. He should also serve as the Rockies' primary pinch runner late in games.

THIRD BASE

J.D. Davis (Astros): Davis, who is hitting .333/.395/.534 at Triple-A, will immediately profile as one of the Astros' top right-handed power bats off the bench, and he should also get some starts at third base, first base and left field against left-handed pitchers. There is a pretty clear cap on his playing time, as it's hard to envision him getting starts against righties, but he could do plenty of damage on a per plate appearance basis.

Christian Arroyo (Rays): Arroyo is on the disabled list at Triple-A Durham with a concussion. Assuming he's healthy in a week or two, he'll be up in September, and will likely get sporadic playing time. There's not a ton of upside, but this will be part of his audition for a 25-man roster spot next year.

Mitch Walding (Phillies): Walding probably needs an injury to get more than the occasional pinch-hit appearance against right-handed pitchers. He's got impressive raw power, but turns 26 in September and still strikes out 30.6 percent of the time at Triple-A.

SHORTSTOP

Jorge Mateo (A's): Yes, Mateo has really struggled at the plate in his first season at Triple-A. He's very raw in terms of approach, pitch recognition, etc.. However, he is on the 40-man roster and is one of the fastest players in pro ball, so he will likely serve in a Terrance Gore role for the A's in September. Gore famously has 21 steals in the majors while receiving just 14 plate appearances (zero hits) across parts of four seasons with the Royals. Mateo has plenty of work to do as a base stealer (just 21-for-31 this year), but he has 80-grade speed and there might not be a player on Oakland's current 25-man roster with even 60-grade speed.

Chris Owings (Diamondbacks): He is 12-for-26 in six games at Triple-A and we know he'll be back up, but he probably won't play enough to be useful in fantasy.

Jose Rondon (White Sox): He is hitting for power (17 HR, .248 ISO in 313 PA) for the first time this year in the minors, and even posted a .245 ISO in 52 plate appearances earlier this year in the majors. That said, he probably needs an injury to open up playing time.

Franklin Barreto (A's): It has been a brutal season for Barreto, both in the majors and at Triple-A -- we have to go back to last year at Triple-A to find the last time he had a strikeout rate below 30 percent. He is basically Isan Diaz at this point. He'll be up and he's got power and speed, but don't look for him to play much, barring an injury.

OUTFIELD

Austin Meadows (Rays): It's easy to see how the Rays' outfield of the future will align. Meadows, Tommy Pham and Kevin Kiermaier will be the starters and Mallex Smith will be a very luxurious fourth outfielder -- at least that's the way I'd align things. Smith has been on a tear at the plate and Pham (foot) is close to embarking on a rehab assignment, so things could be a little crowded initially when Meadows joins his new team (could be any day now), but I expect them to only promote him when they think they have regular at-bats waiting. He is hitting .318 with three home runs and just six strikeouts in 48 plate appearances with Triple-A Durham since the trade.

Dustin Fowler (A's): There is nothing left for Fowler to prove at Triple-A -- he has been one of the hottest hitters in pro ball since getting sent down -- but the A's would rather give him everyday at-bats than have him sit on the big-league bench three or four days per week. That said, he is a long-term upgrade over Nick Martini (and Matt Joyce, who is on the disabled list), and I think he will start to look like a short-term upgrade in the coming days. Like Meadows, he could be up before September.

Byron Buxton (Twins): I probably sound like the boy who cried wolf when it comes to Buxton at this point, but I'm going to die on this hill (some of you probably think I've already died). It has been a disastrous season from both a health and production standpoint, but on the bright side, the price to acquire him in a dynasty league has never been lower. If you need power and, to a greater extent, speed, there are few players on waivers who can match Buxton's upside in the season's final month.

Alex Verdugo (Dodgers): The Dodgers' big-league depth chart seems to shift weekly, but unfortunately it doesn't seem like Verdugo is any closer to getting a much-deserved promotion with a regular role waiting for him. Like Fowler, Verdugo has mastered the Triple-A level (and has been pretty good in the majors too), so it's just a matter of finding him consistent playing time. He will be up in September and will be ready if an opening presents itself.

Eloy Jimenez (White Sox): All of these things are true:
- Jimenez is the second-best prospect in baseball and it's not close.
- Jimenez deserves to be in the big leagues today.
- Jimenez deserved to be in the big leagues a month ago.
- The White Sox have hinted that Jimenez could be up this year.
- It makes literally zero sense for the White Sox to promote Jimenez this year, given the current service time rules.

Do with that information what you will.

Ben Gamel (Mariners): Unlike the next guy on this list, Gamel is doing what a 26-year-old with significant big-league experience should be doing against Triple-A pitching. He is hitting .361/.437/.623 with one home run, three steals and more walks (nine) than strikeouts (six) in 71 plate appearances. Denard Span has somehow earned every at-bat he has received for the Mariners this year, so he would need to get hurt for Gamel to leapfrog him, but Cameron Maybin hasn't been that great, so perhaps Gamel will start to look like an upgrade there in a week or two.

Domingo Santana (Brewers): When the Brewers sent Santana down to Triple-A, I'm guessing they had higher expectations for his performance than what he has delivered (.285/.401/.453, 32.9 percent K rate), especially with half his games coming in Colorado Springs. He needs to be held to a higher standard than guys like Meadows and Verdugo, given his age and MLB experience. We know he will be up in September, but it's hard to see him getting more than a start per week, given his defensive shortcomings.

Raimel Tapia (Rockies): Continuing a bit of a theme with the younger outfielders on this list, Tapia has nothing left to prove at Triple-A, and it's simply a matter of the Rockies deciding to play other guys over him at the big-league level. He will of course be up when rosters expand, but with David Dahl healthy and Ryan McMahon starting to play more, there is no obvious way for Tapia to get consistent playing time in September.

Victor Robles (Nationals): Robles will probably reprise his September role from a year ago, where he served as a pinch runner and defensive replacement. That said, Michael Taylor is already a great option in that role, so I don't expect Robles to see the field much over the final month unless the Nationals deal with injuries.

Clint Frazier (Yankees): Frazier has missed so much time this year with concussion symptoms that it would probably be wise for the Yankees to just shut him down at this point. He has not yet been ruled out for the season, so if he recovers, he would be added to the roster in September. Like with most of these outfielders, however, it will be tough for him to get enough playing time to be a viable fantasy option.

Billy McKinney (Blue Jays): McKinney got off to a slow start with his new team, but has hit home runs in back-to-back games for Triple-A Buffalo, and he figures to get a look in the big leagues in a week or two. As to where he will play, he could platoon with Randal Grichuk or push Kendrys Morales for at-bats at designated hitter. I don't expect McKinney's batting average to be high enough for him to make a significant impact in part-time duty over the final month, but he has legitimate power and will figure into the team's plans in 2019.

Oscar Mercado (Indians): While it was nice to see Mercado traded out of the Cardinals' farm system to a team with very little quality outfield depth, his performance has gone in the tank after the trade (.128 AVG, 30.4 percent K rate), so it's hard to see him coming up and getting a long look for a team with World Series aspirations. He will compete in spring training next year and could get his shot in the first half.

Socrates Brito (Diamondbacks): Brito, who turns 26 in September, has taken full advantage of the Pacific Coast League this year, hitting .325/.388/.555 with 17 home runs and 14 steals in 417 plate appearances. There isn't anywhere for him to play on the big-league club, but if A.J. Pollock or Steven Souza gets hurt, he could get an opportunity.

Jabari Blash (Angels): He will probably never make enough contact for his power to translate in the big leagues, but Blash will be up in September and with the Angels out of the playoff mix, he could get a surprising amount of at-bats over the final weeks of the season.

STARTING PITCHER

Lucas Sims (Reds): It seems like he has been on the big-league radar for a while, but Sims only turned 24 in May. So while most will probably write off guys like Cody Reed and Matt Wisler as bullpen pieces, I'm not ready to give up on Sims as a starter. He has been great in that role at Triple-A this year, both for the Braves and the Reds, and I think he gets a shot in the big-league rotation sometime soon. He has a plus curveball when he is going well, and if he can limit the free passes, there might be some value to be had over the final month.

Brock Stewart (Dodgers): Stewart turns 27 in October, so take this with a grain of salt, but he has a 2.63 ERA, 1.13 WHIP and 67 strikeouts in 75.1 innings in the Pacific Coast League. His inability to miss bats at a higher clip is not a good sign given his age, but he represents a pretty clear rotation option if the Dodgers deal with injuries in September.

Sandy Alcantara (Marlins): Since returning from an axillary infection, Alcantara has given up three runs while striking out 13 and walking two in 12 innings over two starts for Triple-A New Orleans. He still probably isn't ready to be a good MLB starter on a consistent basis -- and may never be -- but he could be a solid streaming option down the stretch.

Luiz Gohara (Braves): He is on the shelf at Triple-A with a sore shoulder, and hasn't pitched since July 29. Even if he gets healthy in time for September, the Braves have enough rotation depth that Gohara probably wouldn't get a look as a starter.

Jonathan Loaisiga (Yankees): He is supposed to start a rehab assignment soon after missing six weeks with a shoulder issue. I'm pessimistic about whether a rotation spot will be waiting for Loaisiga if he gets healthy, but I would recommend scooping him up in deeper leagues if it were announced that he was going to make a start in the majors.

Jefry Rodriguez (Nationals): Rodriguez has struggled in the majors, but has been pitching pretty well at Triple-A and may have back-end starter upside long term. I think he has a chance to be useful as a streamer in deeper leagues in September if the Nationals fall out of the race and decide to give him some more looks.

Enyel De Los Santos (Phillies): Since he was called up to make his big-league debut on July 10, De Los Santos has given up 20 earned runs in 26.2 innings between the majors and Triple-A. He is going through an adjustment period, and I don't see him being a useful fantasy option until 2019.

Stephen Gonsalves (Twins): I'm not sure if Gonsalves will get any big-league starts this season, but I do know I'll be fading him if he does. Not only is his stuff pretty pedestrian, but he sports the worst walk rate (13.4 percent) of his pro career.

OFFSEASON 40-MAN ADDS

Michael Kopech (White Sox): Unlike with Jimenez, I think the White Sox will be able to get away with giving Kopech some big-league starts in September and then sending him back to Triple-A at the end of spring training next year. That's not to say it will happen, but Kopech will inevitably show some flaws against big-league hitters. With Jimenez, he will be the White Sox's best outfielder and possibly their best hitter from the minute he gets to the big leagues, so once he is up, there will be no sending him back down.

Justus Sheffield (Yankees): General manager Brian Cashman had some recent quotes that certainly made it seem like we will see Sheffield in the majors this season, but that was before he was completely ineffective (five walks in 1.2 innings) in Wednesday's start. He obviously still needs to throw more strikes, but his stuff is good enough that he could be a valuable fantasy starter even if he runs a WHIP around 1.35, somewhat reminiscent of Sean Newcomb, although Sheffield is about six inches shorter. He probably won't be very useful in fantasy until sometime next summer.

Josh James (Astros): Left unprotected in last year's Rule 5 draft, James went undrafted, to nobody's surprise. The other 29 teams would soon find out that his stuff saw a massive uptick in the spring, and he is now competing for the minor-league lead with 160 strikeouts in 104.2 innings across stops at Double-A and Triple-A. The Astros finally need a fifth starter Tuesday, and James is scheduled to start Saturday for Fresno, so he doesn't figure to get that call. It would make sense to at least add him to the big-league bullpen in September to see how the stuff plays. They have enough depth that they can easily send him back to Triple-A if they want to play service time games in the spring.

Luis Rengifo (Angels): The top pop-up prospect of 2018 probably comes down to Rengifo and Nathaniel Lowe. That's not to say Rengifo wasn't a known commodity coming into the season, but he wasn't on my preseason top 400. He has skyrocketed through the minors this season, starting at High-A and getting to Triple-A, where he is hitting .303/.372/.443 with more walks (14) than strikeouts (13) as a 21-year-old. It would be a cool story if he were rewarded for this season with a September call-up, but with the Angels out of the race, they may not want to start his clock.

Kevin Newman (Pirates): Newman still doesn't hit for much over-the-fence power, but he seems to have mastered the other aspects of hitting Triple-A pitching (.302/.350/.407, 30 doubles, 10.5 percent K rate). His 28 steals are bit misleading, as he's not that type of burner, but he could still contribute in that category in the big leagues. He is a much better defender than his teammate at Indianapolis, Kevin Kramer, so he would be a better fit for a team still clinging to slim playoff hopes.

Kevin Kramer (Pirates): Kramer isn't the type of prospect teams should worry about playing service time games with. He turns 25 in October, so the Pirates are getting his prime years no matter what. It would be useful to see how he does against big-league pitching in September so that they have a better idea how he would fit into their 2019 plans. He strikes out a bit too much (24.1 percent K rate) given his age, the rest of his tools and his 7.7 percent BB rate. However, if he maxes out he could be a little reminiscent of former Pirates second baseman Neil Walker, churning out some seasons with an average around .270 and 15-to-25 home runs.

Luis Urias (Padres): I thought Urias was going to be up earlier this season, and as it turns out, I was dead wrong. I don't expect him to be up until early next season at this point, but several readers have expressed disappointment in his production this season, and I want to push back on that a little. Yes, his batting average (.275) isn't as high as it has typically been at other stops, but his .140 ISO, eight home runs, 21.5 percent K rate and 40.5 percent pull rate are all career highs at levels where he has spent any significant time. Urias is clearly working on making some adjustments that will allow him to be more than just a high-average hitter. Perhaps that lowers his ceiling in the batting average department, but I still think he'll hit close to .300 or top .300 in his peak seasons. Now that he is getting to more power, I think it is realistic to expect 15-plus home runs in those peak seasons. He still profiles as a No. 1 or No. 2 hitter for the Padres, so there should be plenty of counting stats to go with the lofty batting averages.

Christin Stewart (Tigers): Stewart was hitting .286 on June 1, and is now hitting .250 with Triple-A Toledo, doing very little over the past couple months to make his case for a call-up. He is a lot like Willie Calhoun, in that his ideal position is designated hitter, and it's just a matter of when his team is willing to scrap his development in the field. Mikie Mahtook is the Tigers' current left fielder, so the only reason not to give Stewart a look would be to wait until next year to start his clock, but since the Tigers have waited this long, it's hard to see why they'd promote him for the final month.

Ryan Helsley (Cardinals): He recently began a rehab assignment as he attempts to return this season from a shoulder injury. Austin Gomber and John Gant have done surprisingly well filling in for the Cardinals, so even if Helsley gets all the way back from his injury, there may not be a spot for him in the big-league rotation, but he is a name to file away for really deep leagues in 2019.

NON-40-MAN CANDIDATES

Jesus Luzardo (A's): Not only does Luzardo have just two starts under his belt at Triple-A, but he is running up against an innings limit, as he is at 101.2 innings this year after throwing 43.1 innings last year in his first year back from Tommy John surgery. He should be up in early 2019.

Forrest Whitley (Astros): He is back from his oblique injury but still at Double-A, and running out of time to even get to Triple-A this year, let alone the big leagues. I'm excited to hopefully get to see him in the Arizona Fall League.

Vladimir Guerrero Jr. (Blue Jays): Everything I said about Jimenez applies to Guerrero, except that his team hasn't been weirdly hinting at a potential call-up. His season average is down to .390. It will be fascinating to see where his ADP settles in 2019, but if you want him outside the top 100, you should make sure to draft before spring training starts.

Austin Riley (Braves): If Riley had really been banging down the door, I think he may have been up this year, but at this point I don't see any reason for it. He certainly isn't an immediate upgrade over Johan Camargo, and while he might be a more impactful hitter than Dansby Swanson, the defensive downgrade of sliding Camargo over to shortstop would negate that.

Peter Alonso (Mets): It's the Mets, so who really knows, but I don't see any reason for them to bring Alonso up this year. If he really forces the issue, he could be up in May or June of 2019.

Matt Thaiss (Angels): I thought Thaiss would be up this year when he was raking in June, but he cooled off considerably after that, hitting .263 in July and .196 so far in August. He should be the Angels' primary first baseman for most of 2019, but we probably won't see him this year.