Every NFL team worth its salt has contingency plans when things go wrong. If, for example, you lose two defensive linemen, you should plan to call someone up from the practice squad or have a veteran or two a phone call away. As part of that planning, it’s smart to work out players you might have a level of interest in if injury strikes, so you have reasonable confidence in the guy you’re adding to the team.
I can’t say for certain that’s what animated the team’s decision to work out about seven different players over the last couple of days, but given the sheer number of players working out, it certainly seems like that might be it.