In the 2015 NFL Draft, the running back position is a bit of a mystery with a lot of talent and possibly just as many question marks.

Top tier:

Just about every NFL Draft expert and insider have Todd Gurley and Melvin Gordon as the top two running backs in this year's class. Gurley and Gordon may also be the only two running backs taken in the first round.

Gurley was a preseason Heisman Trophy favorite, but saw his season derailed by an NCAA suspension and a torn ACL. Still, the fact that ESPN and the Big Lead have placed Gurley in the first round is an indicator that teams respect his talent. In six games this year, Gurley ran for an average of 7.4 yards per carry and scored nine touchdowns. Aside from durability, ESPN evaluators give Gurley high marks across the board in the physical and mental aspects of the running back position.

Gordon, on the other hand, is less of a powerful runner than Gurley and more of an agile one, but without the torn ACL. Gordon had a massive season, running for 2,587 yards and 29 touchdowns. Along with WalterFootball.com, several publications have Gurley and Gordon ranked first and second, and being taken late in the first round by the likes of the Baltimore Ravens, Indianapolis Colts and Seattle Seahawks.

Outside the first round:

Without much first-round talent, prospects like T.J. Yeldon, Mike Davis and Duke Johnson could make intriguing mid-round selections. They are not quite as complete as Gurley and Gordon, but each have upside in their own respects.

Yeldon is coming out of Alabama, the school that has produced NFL players like Mike Ingram, Trent Richardson and Eddie Lacy. However, Yeldon does not fit the mold of the above three running backs, as he is more agile, quicker and is adept at catching the ball out of the backfield.

Davis and Johnson did not have the explosive numbers, but they provide solid young running back prospects without costing a high draft pick. They both have room for improvement, but would fit on a team without an immediate need at the position.

In the mid-to-late rounds, look out for Ameer Abdullah, Javorious Allen, Jeremy Langford and Cameron Artis-Payne as dark horse prospects.