One of the largest headaches that face fantasy football general managers on draft day is deciding among running backs that co-exist in a "running back by committee" or RBBC. In terms of actual football, this concept makes sense -- one running back comes in to shoulder some of the burden from another running back and in doing so ensures that both backs will be well rested over the course of an entire game. There are few true juggernauts in the NFL that carry the full brunt such as Maurice Jones-Drew (who played 16 games and carried the ball 343 out of 429 total RB carries for an 80% rate) OR LeSean McCoy (who played 15 games and toted the pigskin 84% of that time on handoffs) OR Adrian Peterson (who controlled the handoffs roughly 83% of the time -- not including his missed games during weeks 12, 13, 14, and 17); however to some extent or another most other backs share some part of their workload. This fact is shown with Arian Foster only handling the ball 67% of the time (not including weeks 1, 3, or 17 in which he didn't play). Please don't misinterpret this as saying that Arian Foster is not important; he clearly is not in any type of significant RBBC situation and is a safe choice to a be top overall selection in drafts come the regular season. The most important (and possibly troubling) RBBC setups are 50/50 or 60/40 splits and the most current potential RBBC resides in Buffalo.
Fred Jackson was a tremendous force over the course of roughly 11 weeks, totaling 1,376 total yards from scrimmage and 6 touchdowns before going down to a broken fibula injury. His backup -- C.J. Spiller -- filled in admirably with 663 total yards and 5 touchdowns from weeks 12-17. At the time (prior to Jackson's injury) there was not a large reason to expect a RBBC; however, the end results from 2011 suggest a need for a revised 2012 game plan for the Bills. In accordance with this thought, Bills GM Buddy Nix has stated that Spiller "can be a workhorse kind of back" and head coach Chan Gailey has said "I wouldn't call it 50-50, but it's closer to 50-50 than it ever has been… neither one of them will get the ball as much as they want to." These quotes coupled with the fact that Spiller wants to be the lead back, as well as, contract extension talks with Jackson going optimistically point to a true RBBC in the works. With this daunting task of discovering who might be the most valuable back in an RBBC rotation, we must look to one of the most defining characteristics of a running back – youthfulness.
Tracking fantasy points per touch for eight RBBC (roughly 50-50 to 60-40) split situations (Miami, Carolina, New Orleans, Kansas City, NY Giants, Green Bay, Indianapolis, and San Diego) in the NFL during the 2011 season using (1pt/10yds, 6pts/TD, 1pt/reception, -2pts/fumble lost) as a scoring standard produced results showing that four of the eight teams had the older RB gaining more points/touch and the other half allowing the younger RB to gain more points/touch.
OLDER > YOUNGER
Darren Sproles (age 28, 1.568/touch) > Pierre Thomas (age 27, 1.142/touch)
Ryan Grant (age 29, 0.769/touch) > James Starks (age 25, 0.694/touch)
Mike Tolbert (age 26, 1.167/touch) > Ryan Mathews (age 24, 0.87/touch)
YOUNGER > OLDER
Jonathan Stewart (age 24, 1.029/touch) > DeAngelo Williams (age 28, 0.907/touch)
Dexter McCluster (age 23, 0.853/touch) > Jackie Battle (age 28, 0.554/touch) > Thomas Jones (age 33, 0.361/touch)
Ahmad Bradshaw (age 25, 0.93/touch) > Brandon Jacobs (age 29, 0.80/touch)
Donald Brown (age 24, 0.794/touch) > Joseph Addai (age 28, 0.553/touch)
Fantasy points per touch do not produce a correlation to help on draft day; however, if you break down the actual ages of each player we do see a striking result. The average difference in ages of the OLDER > YOUNGER bracket ((2 yrs. + 1 yr. + 4 yrs. + 2 yrs.)/4) = 2.25 years. The average difference in ages of the YOUNGER > OLDER group ((4 yrs. + 10 yrs. + 4 yrs. + 4 yrs.)/4) = 5.5 years. Even if you take the difference between McCluster and Battle, instead of McCluster and Jones, the result is still a staggering average of 4.25 years. These numbers suggest that the greater the number of years between two running backs in a RBBC positively correlates with the better fantasy output siding with the younger RB. If this breakdown holds up over the course of the 2012 NFL season, barring significant injuries or loss of playing time, we should see C.J. Spiller having a better fantasy season at the age of 24 (actually 25 in August) than Fred Jackson at the age of 30 (actually 31 at the end of February). This difference of 6 years in age aligns quite favorably with the YOUNGER > OLDER data.
If age is not enough to skew you away from Jackson toward Spiller in a RBBC, note that Jackson has 7 lost fumbles out of 992 carries AND receptions over 5 years for a 0.71% lost fumble rate; while Spiller has 1 lost fumble out of 244 carries AND receptions over 2 years for a 0.41% lost fumble rate. Secondly, Jackson will be 31 at the start of the 2012 season; besides Michael Turner, LaDainian Tomlinson, and Brandon Jacobs, you will be hard pressed to find a usable RB above the ripe old age of 30 for the start of the 2012 NFL season. Granted Jackson does not have the workload history of Turner or Tomlinson, but needless to say, 31 and recovering from a busted fibula is not the same as a healthy 24 or 25 year old. With the real life skewing of coaching schemes toward RBBC game plans, there is a very good chance you will find yourself debating over at least one RB in a significant time-share. If this happens follow the aforementioned game plan in determining your route of action on draft day and good luck.