Mosley is widely expected to be a first-round pick, while West is expected to come off the board on the second day of the draft.
The Bills don't have an immediate need at linebacker or running back, but have little long-term stability at either position. Linebacker Brandon Spikes, the Bills' most notable free-agent acquisition, is on a one-year deal, and running backs C.J. Spiller and Fred Jackson are set to become free agents after this season.
The Bills aren't likely to select Mosley with the ninth overall pick, but he could be available later in the round if they traded down.
The Bills have now used 28 of their 30 allowed pre-draft visits.