Pitching injuries and it's effects are wide. They are documented. They are not understood very well.
As baseball fans we live in fear of pitching injuries. We live in fear of anything new when it comes to pitching because anything out of "tradition" will only make injury rates go up. That's really why so many people hate tandem pitching staffs. But, in reality, many times moving away from tradition is the right way to go because we find things that will ultimately better the sport or the understanding of the sport; i.e. money ball.
We think of injuries with pitchers with athletes like we do with anyone else, we associate it with pain. If there's no pain, there's no injury. Majority of the time, that is true. However, that is based on the assumption that tissues signal pain at every single instance that there is damage, which is not true.
(Aaron West .gif included)
Strength training is the process of tearing muscle tissue down to rebuild it as bigger and stronger muscle. We don't sense that as painful. Yes, some reps are painful, but sub-maximal loads are not typically painful. Especially with adrenaline.
Take a pitcher on the mound in a critical situation. Adrenaline pumping through his veins. He's dialed in. The only thing in his mind is the next pitch. You think he's going to sense micro-trauma? Not a chance.
Eventually micro-trauma adds up to joint laxity...and then a tear.
I'll take this a step closer. While Boddy discusses that there is limited neural innervation of ligaments, that innervation is critical.
It's a small amount of innervation, but it's importance cannot be passed over. Ligaments are the first tissues to detect movement at the joint and signal for muscle activation to assist with stabilization. A torn ligament doesn't do that. A repaired ligament does not do that.
A pitcher that has undergone TJ surgery is at disadvantage for foundational joint proprioception. Yes, he can improve it to appear as much as anyone else. But, the pitcher has to work that much harder.
That is another reason that TJ recovery is difficult and not just another surgery.