I think he has the advantage of height, has solid hands, and is good when plays break down, but I don't think that's enough when he doesn't run good routes and can't learn the playbook. You just can't have a guy out there who isn't running the routes he is supposed to run because it results in Interceptions and the QB taking hits because he isn't where he is supposed to be.
Still I would have liked to have kept him because he does have that advantage and he did make some plays in a small sample size, but it was a numbers game because of the OL injuries. He offsets some of the route issues and not running correct routes by being good when the play breaks down, but first you have to run the play that was called correctly.
If I recall correctly, he was one of the WRs who were not running correct routes last year which resulted in Kodi Burns going. And those are the kinds of lack of attention to detail that Pete Carmichael was allowing to happen. Kubiak is not putting up with that which is likely why Perry was #6 on the depth chart and expendable.