If I were to base this grade solely off the performance of last season, it would not be the type of report card you want to hang up on the refrigerator.
With Lamar Miller and Daniel Thomas splitting the workload, the Dolphins running backs averaged just 3.8 yards per carry, ranking 26th in the league.
To help repair these struggles, the Dolphins added Knowshon Moreno in the offseason. Moreno is coming off a career year in which he set new highs in rushing yards (1,038), rushing touchdowns (10), receptions (60) and receiving yards (548).
The addition of Moreno—combined with the possible emergence of Mike Gillislee—should give Miami a solid three-headed monster in the backfield along with Miller.
However, that may change depending on the recovery of Moreno from the arthroscopic knee surgery he had at the end of June.
Based on his initial four to five-week timetable, Moreno should be back within the next two weeks, but it remains to be seen how healthy he will truly be upon his return.
The success of this unit though will likely come down to Miller and how well he can perform in Lazor's offensive system. The third-year running back seems to be a perfect fit in Lazor's uptempo, spread-it-out offense, and as a result, he seems primed for a breakout season.
Providing Moreno can get healthy and Miller can return to his 2012 form—when he rushed for nearly five yards per carry—the Dolphins could boast a very potent and productive rushing offense.
On the other hand, it's entirely possible that Moreno struggles with his injury throughout the year, Miller repeats his 2013 performance, Gillislee doesn't take a step forward and the Dolphins running game mirrors last season.
For now, they grade out somewhere in the middle.