He pitched the entire 21 season out of the bullpen and ended up hurt. Missed 22. Back to the pen in 23 and gets hurt. He needed something to change and that change was working. He would be foolish to not try and protect that. He is betting on himself to stay healthy for 2 more years so he can get paid.
But maybe you're right and he should have said screw my career, some White Sox fans really want a couple of new prospects.