Thanks for clarifying. Yes I agree even 1 mph can hurt him. My point was that his struggles in ST weren't just velo related, his command was off too, and for a finesse guy with well-below average stuff thats often disastrous like it has in the past for him if he's leaving subpar stuff over the fat part of the plate. He typically has hard hit% better than the average pitcher and average or better exit velos because of the location (plus the addition of the change up last year).
As i said, I don't think he'll be as effective if he loses 1 mph but it's possible he can still stay in the rotation as a below- average SP and BORP. Something like a 4.50 ERA isn't good but not disastrous. If he's worse than that then Rea, Brown, or maybe Assad can step in.