You can't put that in a contract man
I am sure it is not beyond the realms of possibility like, under 4 different managers he has started when available, no matter how anonymous he has been.
So a guy who barely started for Sunderland is going to move to a better team(at the time) and put it into his contract that he has to play when fit and the club are just going to agree to that? He starts because he will follow orders and isn't much if at all worse than the other options for most of his time here