Now, finally, it seems as if both running backs are getting to a place where they're healthy enough to be simultaneously impactful.
Jackson returned to the field for the Bills on Sunday against New England for the first time since injuring his knee in Week 1, and Spiller—who left the game in Week 3 with a shoulder injury—was also active. That leaves Buffalo with two very capable running backs who can go off for 100-plus yards against virtually anyone.
Or so they hope.
Spiller only got a chance to show Chan Gailey what he could do after Jackson went down. He responded very well to the coach's call to action, submitting two straight 100-plus-yard performances and three touchdowns in Jackson's absence. After Spiller got injured, the Bills were hoping that Jackson would be back the following week to spell him.
They got their wish. And they also got Spiller back. Now that Gailey knows he has two running backs who can both be the No. 1 guy, he has a predicament every coach would love to have.
Much of the outlook for Jackson depends on health—not only his own, but Spiller's as well. If Jackson proves that he has fully recovered from the knee injury that ruled him out of Weeks 2 and 3—and he can go a long way toward establishing that on Sunday against New England's formidable rush defense—he'll remain the Bills' No. 1 guy.
Jackson may be getting old (he turned 31 in February), but his output for the Bills over the last three years has provided the necessary evidence that he's still the go-to guy. Since his 1,433-yard season in 2009, he's had two consecutive seasons in which he's accumulated 1,000-plus yards and at least six touchdowns, even in an injury-riddled 2011, when he was placed on injured reserve with a broken bone in his right leg.
Prior to sustaining that injury, though, Jackson made nine starts and played in 10 games. In six of those 10 games, he finished with at least 100 rushing yards, and in a five-game stretch early in the season, he registered all six of his touchdowns.
Obviously, it's hard to predict how effective Jackson is going to be from here on out. We don't know how healthy he really is. We also don't know how many carries he's going to get if Spiller stays healthy as well (in Jackson's absence, Spiller got 14 carries in Week 1 and 15 in Week 2).
Most likely, these two are going to split time as the season progresses and as they continue to recover from their various ailments. If Spiller continues to impress, it's possible that he could move into a bigger role, especially given the fact that he's much younger and just starting to emerge as a premier offensive talent.
But until then, Jackson will still see his fair share of field time. It may be less than he's been used to—in 2011, he averaged roughly 17 carries per game until he went down—but expecting him to get 11-15 carries per game is realistic. If Spiller struggles (or gets injured again), it's going to be more.
And if he gets that many carries, he should be able to put up the kind of yardage we've expected out of him over the last few years.
The good news for both Jackson and Spiller is that the Bills aren't making a name for themselves with their pass offense in 2012. This offense is all about the running game, and in that sense, this team's success depends largely upon the two of them. Both of them hold the keys to this offense, so obviously, both of them should continue to be key components of it.
Sunday's matchup against New England will tell us a lot about what to expect from this backfield duo and how Gailey plans to utilize it going forward. Until further notice, though, Jackson is still expected to be the top guy.