Stephen Strasburg was shut down over the weekend despite only throwing 159.1 innings this season. The rumored 180 limit was never reached (via Yahoo! Sports); in fact, the original 160 limit was not even reached.
All of the ballclubs' rules and myths of arm damage and pitcher protection are being stretched more than ever. Arms are worth more money now and agents are making sure that their clients are not put in any situations that could risk further damage to the body that is responsible for making millions.
There are statistics and reason for both sides, but for the most part, these injuries are going to happen one way or another. It comes down to common sense: The arm is not meant to throw the way a pitcher pitches; the natural throwing movement would be underhand, so anything that varies is, in essence, damaging the arm.
There are signs that innings limits are not the practical thing to do for the game of baseball and the examples are apparent all around the league.