Steven Tyler Joins Red Sox, Yankees as Stars Appear at Fenway Park Friday (Photos)

When the Red Sox and Yankees face off, you can expect to see plenty of superstars around the ballpark. On Friday, one could see Adrian Gonzalez, Derek Jeter — and Aerosmith lead singer Steven Tyler.

The two teams were not only competing for a win Friday night, but also for sole possession of first place. Superstars certainly have an impact, but role players like Josh Reddick are always expected to contribute, too.

Check out pictures of superstar athletes, superstar singers and role players here >>