Collette Calls: Breaking Down Aaron Nola

It was a big driver while I could not shut up about James Paxton this offseason, and I'm getting the same gut feeling watching Aaron Nola these days. Saturday, he defeated the New York Mets going seven innings, allowing four baserunners, one run (solo HR) and striking out eight. Over his last 10 starts, Nola is 6-2 with a 1.71 ERA, a 1.00 WHIP, a 29 percent strikeout rate and has permitted five home runs in 68.1 innings in that time. As the pundits like to say, "he's shoving!"

For visual representation of what he looks like lately, I offer two animated gifs from one of my favorite follows on Twitter, @PitchingNinja. Seriously, open a new tab and follow this guy because his animations of nasty pitches are fun to watch throughout the day. First, Nola's curveball:

Aaron Nola, filthy 77mph Curveball movment. pic.twitter.com/JfvUnVjtKO

— Rob Friedman (@PitchingNinja) August 13, 2017

Aaron Nola, 90mph Blitz Ball. pic.twitter.com/KaPU2rZuaL

— Rob Friedman (@PitchingNinja) August 13, 2017

Getting back to Nola; his season has been a tale of two halves, and the first half was abbreviated by a stint on the disabled list. Nola went on the disabled list with a lower back strain after his third start on April 20 and initially hoped he would only miss one to two starts. He ended up spending five weeks on the disabled list and did not return to the majors until May 21. Earlier, I referenced his last 10 starts, but these were his numbers in the first nine starts of the season before that streak kicked off in earnest: 3-5, 4.76 ERA, 1.35 WHIP and 22 percent strikeout rate over 51 innings.

Now, let's see those numbers next to one another so we can see where the areas of growth are happening:

By pitch mixture, Nola has not really changed much up as he has always had a four-pitch mixture, and while he has tinkered with his usage of his four-seamer from time to time, the mixture has remained rather consistent this year (data per BrooksBaseball.net):

By overall whiff percentage, we begin to see a contributing factor to his improvement:

Nola's curveball has generated an increasing number of whiffs month over month. The league-wide rate for swinging-strike rates on curveballs this year is 13 percent; Nola has been at or above that rate every month of this season and has been well above it since the end of June. Nola's curve has generated 50 swings and missed in July and August (8 starts) compared to 49 over the first three months of the season (11 starts).

It is a little thing, but Nola has been throwing more first-pitch strikes during this run of success. The first pitch strike, by itself, is not the linchpin to success for a pitcher. The
real magic is what happens with what a pitcher does with their first three pitches. If the pitcher can get into a two-strike count within those first three pitches, it forces the batter to expand the zone and protect on the edges and gives the pitcher a larger advantage. Nola is getting a first pitch strike 66 percent of the time in this run, and getting ahead early is allowing him to throw fewer pitches in the zone as he uses his curveball to get batters to swing at pitches they would normally spit on if they were up 2-1 or 3-1 in a count. Note the percentage of curveballs and changeups hitters are swinging at month over month for Nola:

Both the curve and the change are pitches that ideally end up out of the strike zone and generate swings and misses or poor contact. Lately, Nola is getting ahead early and then using his pitches to entice batters to swing at pitches they ultimately cannot reach with the bat. If we can simplify the success to pitching, it is get in and get out and move on. When pitchers work in the zone early, they can work out of late and still find success. For example, when Nola throws pitches in the strike zone, batters make contact 86 percent of the time, but when they swing at pitches out of it, they make contact 56 percent of the time. By getting ahead of batters and forcing them into protect mode, he has reduced their ability to make contact by 25 percentage points.

Lastly, Nola has seen an increase in his velocity in 2017 over 2016, and even within this season once he got the back strain issues behind him:

Overall, we have a pitcher throwing harder, throwing more strikes, and attacking batters to put them on the defensive. It is important to remember that every pitcher has the advantage over every hitter in any matchup, but it's how well or how poorly the pitcher executes his plan is the biggest influence on the outcome of any particular matchup. Aaron Nola has it all clicking and is working in some kind of zone. He has now allowed more than two runs in any of these past 10 starts and has only once walked more than two batters in that time. Using our auction values calculator, we see how Nola ranks against some of his starting pitching peers to date: