Wally Pip was the player who sat out for an injury and was replaced by Lou Gehrig for a game or 2130. The implication was that you should play through pain or lose your position. All three resulted from overuse and all three were afraid to report their pain. The position player at least told his dad who got him to a doctor early.
No, it isn't inevitable by any means. Just like a lot of things it is a bit more likely to recur once it has happened the first time. There are a lot of success stories with conservative treatment. One of the more recent success stories was Takashi Saito who used PRP as a treatment rather than surgery. I'm not sure but I think Ervin Santana also took the conservative route and finished this season well.
It is important to check with the doctor as to success rates with conservative therapy because if it turns out to be more than just micro tears then the rehab takes a long time and there's a fair possibility of still having to have the surgery.