Davis has the skill set to be a feature NFL 'back - he's big, fast, and fierce competitor. He runs downhill, pass blocks well, doesn't shy from contact, and has the explosiveness to break a long run once he's in the open field. As a sophomore in 2010, he tallied 1322 rushing yards to lead all SEC running backs - beating out a few guys with names like Mark Ingram, Trent Richardson, and Marcus Lattimore.
Injury cost him the entire 2011 season, and despite showing flashes of his talent in 2012 (a 64-yard TD against Texas A&M comes to mind), he was largely ineffective playing behind a patchwork offensive line.
His poor production in 2012 cost him dearly in the draft projections, but a strong showing at the NFL Combine has mitigated some of those concerns. He clocked a blistering 4.37 in the 40 yard dash, to go along with 31 reps on the bench press - both of which ranked 2nd out of all running backs at the Combine.
The 800 lb. gorilla in the room is that he's injury prone, and he always has been. Both his junior and senior seasons of high school were cut short by a fractured collarbone and broken right ankle, respectively. He enrolled early at Arkansas, only to break his right ankle again during the spring practice (he was able to return in time for the 2009 season). The next spring, he broke his collarbone during the annual Red-White scrimmage, which made his breakout during the 2010 season all the more impressive. And less than a month before the 2011 season began, Davis broke his left ankle during fall camp and was sidelined for the entire season.
Any way you slice it, that's a troubling injury history - for anyone else, that might be career-ending. There's something admirable about Davis' dedication to rehab and unwillingness to give up after repeated set-backs, though.
Injuries aside, he sometimes has trouble gaining yards after contact (despite not shying away from said contact), has occasional lapses in ball security, and since he's most impressive running in space, he needs to play behind a decently functioning O-line.
Davis has all the tools that he needs to be successful in the NFL, but his injury history is definitely working against him. Even with those concerns, based on his skill set and his performance at the combine, he's a solid 3rd or 4th round pick. He falls any lower than that, and he's an absolute steal. If he can stay healthy and get picked up by a team with a competent O-line, he's going to have a shot at being a very successful and dependable running back in the league.