Braves' pitcher Tommy Hanson informed the media that he has worked in the offseason to change his pitching delivery in order to take some stress off his shoulder and quicken his motion to the plate. He ended 2011 on the DL, a season in which the Braves collapsed down the stretch and failed to reach the postseason.
Hanson says he is now separating his hands later. This gives his throwing arm less time to come full circle and deliver the pitch, which means it can't get into the awkward cocked position that he demonstrated before. Hanson acknowledged that with his old mechanics he felt like he was throwing entirely with his arm. I'll say - his old delivery was a little painful to watch, so one can understand the stress that his shoulder (and likely elbow) was under. With the new timing of his later hand separation and therefore quicker delivery, his arm won't be ready to throw quite so soon. He'll end up using the energy generated by his hips to pull that arm forward and thus take stress off the arm itself.
Here is a great video analysis of Hanson's mechanics by Dick Mills from several months ago. Mills contrasts Hanson's old delivery with that of Daniel Bard of the Red Sox, and recommends to Hanson that he make an adjustment. I remember seeing Bard pitch in high school for Charlotte Christian - I was struck by how effortlessly the ball seemed to jump out of his hand. That's what whole body mechanics and perfect timing can do for a pitcher.
Pain or injury from improper mechanics may not be felt at at the youth level. But the damage can be done there. Get it fixed before that happens.