Pop will spare him from what exactly? He is 25 years old. He had an MVP type season last year, and yet he is still below his ceiling. More playing time means more fatigue sure, but it also means accelerated learning that comes with playing against the basketball's best.
Maybe we should find out just how much of the load he can carry, and for how long, before making an arbitrary decision is all I am saying. Pop played Tim Duncan about that many MPG when he was winning MVPs, so it is not like it is unprecedented.