It's probably a matter of needing that cap space immediately. I don't expect Veach to pull the trigger unless he has some other deals in place that requires the money saved from Watkins' release. I believe the same is true for Colquitt as well, I doubt the plan is to keep him for 2020 but there's no urgency to pull the trigger yet. As things currently stand even if they want to let Watkins go waiting on a trade partner makes more sense.
In the end I think the plan is letting Watkins go to clear up some space instead of a bunch of other guys that has less impact.