Honestly, I don't blame the way he was treated in Japan as much as I do the way the Yankees abused him.
Playing higher-quality talent, on shorter rest, and being relied on as the ace in place of Sabathia, he threw a lot of his "junk" under more stress, and more often. It was poor handling. I even commented to my son in the last couple of starts that something "looked off" with him. He should have been temporarily shut down two weeks ago.
Anyway, I'm in the camp of shut him down for the rest of the year. The Yankees need to be sellers for once. Dump whatever you can, eat some salary, and bring back some prospects. It's time to rebuild a future for this team. Age has caught up not just to the vets, but is now having trickle down effects on the youth.