There isn't a consensus regarding who the top running back in this year's NFL Draft is, but Auburn's Tre Mason would certainly be in contention to be the first RB drafted.
That is, if he wasn't dealing with an injury that required surgery this offseason. The NFL Network's Ian Rapoport recently reported that Mason needed surgery performed on his wrist:
#Auburn RB Tre Mason a surprise visitor to Combine medical rechecks, per source. Needs wrist surgery post-draft, should be back by preseason— Ian Rapoport (@RapSheet) April 25, 2014
Mason has since publicly denied that report, but now Jene Bramel of FootballGuys.com is also reporting Mason does in fact have a serious wrist injury:
Source confirmed to me yesterday what @RapSheet reported last week: Tre Mason has fractured scaphoid that had not fully healed in February.— Jene Bramel (@JeneBramel) May 4, 2014
Mason is viewed as a Top 50 prospect and would go fairly early in the second round if not for this injury.
If he does end up having a surgical procedure that knocks him out until the preseason, that means he'll miss most of his team's training camp.
When healthy, Mason is an electrifying runner who played great against elite competition, including Florida State in the BCS National Championship: