I blame the WBC. Too many minor leaguers and never wases who can't throw an effective brushback without hitting him, or at least his ego.
Even if it did not happen in the WBC, how do you know he would have been playing or taking batting practice when he was hit?
Even if he was not hit, he could have been strengthening his thumb rather than playing in the WBC. he used his tendons then.
It is all the WBC's fault.