Can Alfred Blue, Jonathan Grimes Save Texans' Run Game in Foster's Absence?

To discern just how much running back Arian Foster's new injury means to the Texans—and thus how much of a drop-off there is from him to Alfred Blue and Jonathan Grimes—we need to unfold the layers of Foster's statistical production.

Arian Foster's current value to the Houston Texans can vary wildly depending on whom you ask and what statistics you wish to use.

Foster hasn't been a statistically dominant back on a seasonal basis since 2010, when he finished fourth in Football Outsiders' DVOA.

The key difference between then and now appears to be an offensive line that aged poorly. Offensive tackle Eric Winston was replaced by the wildly inconsistent Derek Newton. Guard Wade Smith grew too slow to reach the second level. The 2010 Texans had the perfect mix of blocking and vision.

But a back that relies on vision, like Foster, is naturally going to rely more on offensive line play than a back that excels at avoiding or powering through tackles.

This has evidenced itself in the advanced statistics, as only Foster's injury-shortened 2013 season has been far above average on a carry-to-carry level:

Year	Carries	DVOA (Rank)	DYAR (Rank)
2010	327	18.0% (4)	372 (2)
2011	278	2.3% (24)	122 (14)
2012	351	-1.6% (20)	105 (13)
2013	121	11.4% (8)	99 (19)
2014 (Through Week 2)	55	-6.5% (24)	5 (22)

Foster still had fairly impressive cumulative numbers, of course. He even had single games that were excellent. While the pass offense was shriveling up against Baltimore and New England in back-to-back divisional round matchups, Foster kept the Texans in each game.

Under the new regime, Foster also looked to be a key component in the passing game. Texans head coach Bill O'Brien was quick to anoint Foster the passing game back—filling the "Kevin Faulk" role, as he called it. 

The Texans ran a lot of empty-back sets early against Washington, with Foster out wide.

What Foster's hamstring injury tells us is that, regardless of how O'Brien wants to use Foster, the initial plans to make Foster a workhorse back were ill-fated. Foster's body simply can't hold up to a workload of 25 carries per game at this point.

Should Foster's absence bleed into next week—ESPN.com is reporting he's day-to-day—it will lead to expanded opportunities for rookie sixth-round back Blue and veteran waiver-wire claim Grimes.

Blue has been a bit of a revelation compared to what I expected before the season. The rookie out of LSU was perhaps not all the way back from his season-ending knee injury suffered in his junior season of college, which explains why he was a middling option for the Tigers in 2013.

Blue has shown more power than I anticipated, but the vision still comes and goes.

One example of this was when O'Brien went for it on 4th-and-1 at the beginning of the third quarter in New York last week. Blue had a hole but ran right into Newton's shoulder pad to kill the drive.

Credit: NFL Game Rewind

Grimes showed well in 2013 in his limited sample size (21.7 percent rushing DVOA, 22.0 percent receiving DVOA per Football Outsiders). I think he's a solid depth back, and I'm a little surprised Blue has been given the bulk of the carries over him to this point. I'd think on talent alone, a timeshare is a little more appropriate.

Where the Texans will miss Foster most is in passing situations.

Foster is by no means an excellent blocker, but he knew his assignments and has shown the ability in the past to be a positive as a receiver. Blue had just 13 catches in four seasons at LSU, and both Blue and Grimes are iffy as pass protectors.

Whether you believe either player is a downgrade on Foster or not depends on just how high you were on Foster to begin with.

In my mind, Foster is a noticeable loss but not a devastating one. Most of Blue's yardage this season came on one 46-yard run where the only person to touch Blue was one of his own blockers, whom he'd run into momentarily.

Losing Foster will hurt in the sense that O'Brien's main goal has been to chew clock with a lead. Blue—whom I would call a poor man's Ben Tate—is going to make that harder in the event that the Texans get a lead.

He's also poor enough as a pass protector to force the ancient Ronnie Brown onto the field.

But on the whole, this doesn't really change the dynamic of Houston's offense much. Only winning decisively on defense against Oakland and Washington allowed the Texans to set up those game scripts in the first place.

The Texans were never going to be able to fade their entire schedule in that way. They'll need Ryan Fitzpatrick to deliver some big plays to sustain their offense.

That, more than what percentage of Foster Blue can be, is the question that will drive the running game production going forward.

Rivers McCown is the AFC South lead writer for Bleacher Report. His work has also appeared on Football Outsiders and ESPN.com. Follow him on Twitter at @riversmccown.