The only thing I can guess at is that they need scoring at the AHL level, but it looks like they're in 7th place in their division so still seems random. I guess Criscuolo's cap hit is around $100k less than Weatherby and the Sharks have less than a million bucks in cap space, so this could offer slight flexibility in the event of a call up but that's probably grasping at straws.
This at least helps the Wings with the veteran logjam in the AHL too, hopefully no more Vrana scratches.