Because it can, with time, become more stable. There's no guarantee it won't pop out the first snap but why not wait and see if it gets strong enough for him to try? If it doesn't, he won't play. But if he gets the surgery, he's guaranteed not to play. If Jake was a "pansy", he'd had the surgery right away so the pain would be gone. He's gutting it out in an effort to get back out there.