The Colts' selection of Delone Carter out of Syracuse in the fourth round came as a surprise to many. Carter is a big back who Indy selected to help with the third and short situations as well as the 'four minute offense' to run clock out at the end of games.
Going back to 2003, there have been 22 running backs and full backs taken in the fourth round. Most struggled to see the field in their rookie season. Only four players managed to gain 500 yards rushing in their rookie season. 13 of the 22 failed to rush for even 200 yards. The most immediately successful was Houston back Domanick Williams who posted 1031 yards rushing his rookie year to go with 351 yards receiving. Williams and Le'Ron McClain (a full back) were the only backs to become regular starters in their rookie years.
Two 4th round backs since 2003 have gone on to Pro Bowls, however. The most successful back recently taken was Marion Barber who played in a Pro Bowl with Dallas. Le'Ron McClain also has two Pro Bowls, but that is in part because he's virtually the only fullback left in the AFC. Other notable 4th round backs include Darren Sproles and Tashard Choice.
The Colts history of running backs this decade has been a good one, but not one that will likely help us in this endeavor. The Colts have draft three running backs in the first round since 1999. Edge James was obviously the best, followed by 1,000 yards for Joe Addai in his rookie year. The other three backs Indy drafted include Anthony Davis (never played), Brian Allen (4 games), Mike Hart (2 carries rookie year) and Don Brown. Brown posted just 28 carries and 281 yards his rookie year as he battled injuries. Three other Colts rookies were undrafted players (Keith, Rhodes, and James), but none of them are necessarily good analogs for Carter's size and role in the offense. They do show, however, that the Colts will hand the ball to rookie backs.
One thing we can be sure of when it comes to Carter is that he'll be splitting carries. The Colts haven't had a back carry more than 261 times since the departure of Edgerrin James. Based on the way the Polians have spoken about Carter's role in 2011, it's unlikely he becomes the feature back, though some draftniks have said he has that kind of body/ability.
So what can we expect from Carter? 50 carries would be on the extreme high end for a fourth round back, however, the Colts have shown they'll give carries to anyone who can produce (Kenton Keith picked up 122 in his season in Indy). The Colts clearly plan to use Carter late in games to grind out 10 yards on three runs, so it's reasonable to expect him to pick up 100 carries. The biggest question for Carter's usage may come down to what happens with Addai. If Addai is not resigned (and he has gotten a restricted tender), then Carter can expect a bigger role in the offense as the number two back.
Ultimately, Carter will likely become the most popular player in Indianapolis. Fans love backup running backs who 'run hard' and 'don't dance'. Almost all fourth round backs make their NFL team, so it's reasonable to expect Carter to play in all 16 games and pick up 75-100 carries, with around 400 yards and 3 or four touchdowns. If his yards per carry is anything close to 4, it would be a coup. However, because the yards he is asked to get will be particularly difficult ones, fans shouldn't worry if his YPC is lower than other backs. He needs to pick up 2 yards on 3rd and 1, not 5 yards on 1st and 10. In all, such numbers would actually be a remarkable season from a fourth round back (3rd or 4th best in recent years), but given the Colts stated plans for him, such expectations are reasonable, if not conservative.
Going forward, there's no reason to think Carter can't have a nice career. A best case scenario for Carter would be the career of Marion Barber. He's a big back in a high powered offense who has to split carries. He's topped 800 yards three times (though never 1,000). He vultures a lot of touchdowns and made a Pro Bowl. If Carter can get anywhere near that level of production, he'll have proven to become a wonderful selection. He's coming into the perfect situation for a running back of his ilk.
It's fair to have slightly higher than normal expectations for Carter because of the situation he's entering. Ultimately, his value will be measured by his 'success rate' late in games and on tough thirds and fourths and shorts. If he picks them up, his yards and yards per carry won't really matter at all. If he doesn't, then nothing else he produces will mean as much. Ultimately, he should form a nice 'thunder and lightning' combination with Donald Brown as both backs bring completely different skills to the table.