From what I've gathered, a large contributing factor into pitchers getting injured more often is everyone is throwing harder. There seems to be an argument for contributing factors, but it seems obvious to me that pitchers throwing harder is a large driving force. They have all these guys in specialized labs now, coming out with better stuff and throwing harder, but the downside is injury.
You can almost assume at this point, that every MLB is going to have some kind of major surgery at some point in their career.