The resurgence of one previously out-of-work major league pitcher has increased demand for a controversial new procedure utilizing stem cells that could usher in advances in athletic-injury treatment so effective they seem to turn back the clock.

But there are questions about the extent to which the attention-grabbing stem cell aspect of this new therapy helped Bartolo Colon, who has become the poster boy in this nascent area — or whether he benefitted primarily from particularly successful, but decidedly traditional, surgery.

Colon was an elite hurler for the Cleveland Indians and Anaheim Angels before age, injuries and workload took their gradual toll on his right shoulder. His baseball career seemed to be over when he was released by the Chicago White Sox during the summer of 2009, thanks to recurring bone spurs in his elbow.

His fastball speed had dropped several ticks. For a power pitcher like Colon, that often signals the beginning of the end.

And yet Colon has emerged this season with a fastball on par with his 2007 numbers, and his strikeout rate (if it keeps up) would be the best of his career since 2000. Testing for performance-enhancing drugs has never been more rigorous in baseball, so how did this happen to a 38-year-old has-been?