No, this isn't a reactionary post due to his poor performance tonight. This isn't about a demotion. Given his expected workload coming into the season, he's going to have to go down at some point. In a perfect world, I think that time would be now as he's struggled with command, particularly of the FB, in the last two outings. Unfortunately, his probably replacement, Bartolo Colon, isn't stretched out to come up right now.
They play 2, have a day off, then play 14 straight. Bart pitched 3 IP (49 pitches) on Saturday, 5/10. Clay's rotation spot will come up again on 5/18 at home against MIL. Not enough time to pitch Bart again on Thursday 5/15 and then replace Clay. His next start would be 5/23 in Oakland. Bart should be stretched out after his 5/20 start, so I suggest they make the move after the 23rd (provided there are no setbacks - regardless of Clay's performance in those two games).