I'm not faulting the attempt. I'm faulting the continuation, after it seemed clear he was better suited for the pen, and his health concerns should have sealed the deal.
Blame one- blame them all. At this point, does it matter? Just stop using him as a SP. I'd say the same about Houck, although he has proven he can go 18 batters deep more often than not, and these days, that makes for a fine #4 or #5 in many winning team's plans. I'm not sure about Crawford, but I'd prefer to not try, again. Just leave him as a long man, where he was doing very well, this year.
He started the year in the rotation:
8.00 ERA
Then, 1.66 as a RP'er in 8 games (6 at 2 or more IP)
Then back to the rotation:
4.47 ERA, which is not all that bad (4.6 IP per GS)
Just make a plan where Crawford, Houck and Whitlock are safely placed in the pen with little chance of being needed as a SP.