After examining the best keeper wide receivers and quarterbacks over the last couple weeks, it's time to move on to my favorite position in football: the running backs. The position has evolved so much over the past 15-20 years that the turnover among star running backs is becoming increasingly faster, and for keeper leagues the age at which you start to consider a replacement for your stud is getting younger by the day. It used to be the player turns 30 and he falls off a cliff. And sadly that was just a few years ago. Now if my star back is 28 I'm looking for a fresh face.

With that in mind, I was tempted to consider my keeper running back crop within just a 2-year window. Ultimately though I decided against it and so I've ranked these ballcarriers based on the same guidelines with which I ranked receivers and quarterbacks. I looked at each player's recent production, their ability/potential and their age at the start of the 2012 season in September and considered it over the next three years. If starting a keeper league today or deciding who to hang on to for next season, I would take the following 10 before any other backs.

1. Arian Foster, Houston Texans (6-1, 229 ; age 26)
Foster reportedly played all of his 2010 breakout campaign on a torn meniscus. He then battled a hamstring injury during the first half of a very strong 2011 encore that saw him miss three games and share carries with Ben Tate, possibly the league's best back-up running back. And all he did in those two seasons was rack up 4,061 total yards and 30 scores. Oh and that doesn't include the 336 total yards and three touchdowns he put up in two playoff games. There is flat out no way anyone else can top this list.

2. Ray Rice, Baltimore Ravens (5-8, 212 ; age 25)
The Baltimore offense goes as Ray Rice goes. The league knows this and yet for three seasons it has done little to slow him down. Rice has averaged 1,961 total yards and 10 total touchdowns per year over those three seasons. He's just 25 and could be even better if the Ravens improve a mediocre offensive line. After taking over goal line duties last year and boosting his scores way up, there's really no downside to this mighty mite's game.

3. LeSean McCoy, Philadelphia Eagles (5-11, 208 ; age 24)
McCoy has been extremely efficient the past two seasons, piling up over 1,600 yards each year and totaling 29 touchdowns, including 20 in a monster 2011 campaign. He may be the most elusive back in the league in small spaces and has the speed to tear chunks out of a defense, as evidenced by his 4.8 career yards per carry and 2011's league-best 14 carries for at least 20 yards. Add in the nose for the end zone McCoy displayed last year and the limited wear and tear he's experienced to his body and you have the recipe for an annual stud.

4. Ryan Mathews, San Diego Chargers (6-0, 218 ; age 24)
The biggest thing (both literally and figuratively) holding Mathews back from a complete explosion in 2011 is gone from San Diego. The carry-robbing, touchdown-vulturing mini tank that is Mike Tolbert is now in Carolina, leaving Mathews to handle the backfield duties as a feature runner. While there are some durability concerns, Mathews' combination of speed, strength and elusiveness gives him too much upside to stay away from. The stretch run of 2011 (511 rushing yards and three scores over his final five games) also proved that he could power through nagging injuries and be highly productive while doing so. Expect an improved offensive line and a heavy workload to make Mathews a beast.

5. Trent Richardson, Rookie (5-11, 224 ; age 22)
Despite not even knowing what team he will suit up for over the next three years, it's hard to see Richardson being anything short of a stud. Whether it's in Cleveland or Tampa or elsewhere, expect this complete back to pile up in the neighborhood of 4,500 total yards in his first three seasons and at least between 24 and 30 scores. With his blend of speed, power and vision, Richardson is the next big deal at running back and all stats, measurables and circumstances aside, he's a can't miss guy who will produce from Day 1 at a very high level. The comparisons to Adrian Peterson are a bit lofty, but he compares favorably to a Marshawn Lynch with better wheels and much more potential as a receiver.

6. Chris Johnson, Tennessee Titans (5-11, 191 ; age 26)
In an uncharacteristically down year for Johnson, the former 2,000-yard back still finished with over 1,450 total yards and was tied for third in the league with 11 carries of at least 20 yards. Considering that it took him awhile to get his legs all the way back into game shape after a holdout and that he was running behind a line that consistently let him get buried in the backfield, those numbers aren't too bad. CJ2K still has all the speed and the addition of 7-time All-Pro guard Steve Hutchinson and a full offseason of work will give him plenty of opportunities to showcase it in the immediate future.

7. Maurice Jones-Drew, Jacksonville Jaguars (5-7, 208 ; age 27)
Though he's the oldest on this list and boasts the most career touches, Jones-Drew is also one of the most durable of the bunch, having missed just three games in six seasons, including just two in 2010 when he played most of the year with an injured meniscus. His bowling ball body is built to last, and after racking up 1,980 total yards and 11 scores last year despite playing for an offense that finished dead last in total yards, it's clear no situation could hinder MJD from producing.

8. Marshawn Lynch, Seattle Seahawks (5-11, 215 ; age 26)
Beast Mode will still be the preferred method of attack for the Seattle offense despite the addition of Matt Flynn. And with the upgraded passing game opening more running lanes for Lynch, look for another big season of scores and yards for a player with a lot more left in the tank after receiving just 322 carries between the 2009 and 2010 seasons.

9. DeMarco Murray, Dallas Cowboys (6-0, 227 ; age 24)
In his first six career starts Murray piled up a remarkable 761 rushing yards. So while there are some legitimate concerns with his future—such as durability, the Dallas offense and touchdown production—there's also undoubtedly a lot of talent in this young back. Murray has the size, speed and versatility as a receiver to be a yardage machine if he can remain healthy and the Cowboys give him the touches that his skillset warrants.

10. Darren McFadden, Oakland Raiders (6-2, 210 ; age 25)
The ultimate risk/reward player, McFadden has the upside to finish as the top fantasy back in the league if he can just survive a 16-game slate (something he has yet to do in four seasons). There's simply nothing he cannot do on the field. McFadden fights for tough yards between the tackles, can break any run to the house and is superb as a receiver out of the backfield. When healthy, the sky really is the limit for the yet-to-be 25-year-old.