Raheem Mostert, running back for the Miami Dolphins, did not participate in Monday's practice due to an undisclosed injury. The Dolphins have not released an official injury report, but it is possible that Mostert is simply getting a veteran rest day. The backfield situation will need to be monitored closely, especially with De'Von Achane returning from IR. If both Mostert and Achane are cleared to play, they will likely split time as co-starters.