5. J. A. Happ, 2007-2010 Phillies
J.A. Happ has played for eight teams (including two stints with the Blue Jays) so far in his career, so don’t feel bad if you forgot where it all began for him.
The Phillies drafted Happ in the third round of the 2004 draft. By 2006, he was named their eighth-best prospect. He made his debut on June 30, 2007, got shelled by the New York Mets, and was sent back down to the minors.
After beginning the 2008 season with the new Triple-A affiliate Lehigh Valley IronPigs, Happ returned to the bigs on July 4. He was sent up and down a few times throughout the season, and was added to the team when the rosters expanded in September. Over eight regular-season games (four starts) that year, he posted a 3.69 ERA. He also pitched in the NLCS, helping the Phillies to their second championship.
The following season, Happ became a full-time big-leaguer, pitching in 35 games, including 23 starts. He compiled a 2.93 ERA over 166 innings.
In 2010, Happ was off to a strong start when the Phillies traded him and minor leaguers Anthony Gose and Jonathan Villar to the Houston Astros for Roy Oswalt.