exactly this.
Arizona plays Boston, Buffalo, Dallas, Chicago and Anaheim between now and the deadline. Stone has been playing 20 minutes a night for them. What do you think ARI gets if Stone gets hurt in one of those games? If ARI doesn't think the value is going to go up by much (say a 3rd and a 5th vs a 3rd and a conditional 5th), there's really no reason to wait to pull the trigger. I mean even if he thought he might get a late 2nd, that still might not be reason enough to pull the trigger.