You just don't understand logic. It's tragic really. So, let me break things down for you into itty bitty pieces so your tiny little brain can process.
Clay Buchholz has proven to be fragile. He's missed time in every one of his seasons and his IP max was 170. He is signed to a big money contract, but when you consider that he's not making 10-15 of his starts a year, that money could be used elsewhere. If Clay had one solid, healthy season, it might push his trade value up to where he'd get a good return on his value before another injury cropped up. He was on his way to a very solid, ace like season last yr. Knowing his history, he wasn't going to be able to sustain that year after year. Had he completed last season with 30+ starts and 200IP, his trade value would have jumped. I think the sox would have sold high on him. But, alas, his shoulder gave way and he couldn't finish, as usual. Now, he's a shell of himself.