From BR Bullpen
Sean Daniel O'Sullivan
- Bats Right, Throws Right
- Height 6' 1", Weight 220 lb.
- School Grossmont College
- High School Valhalla High School (El Cajon)
- Debut June 16, 2009
 Biographical Information
Sean O'Sullivan was drafted by the Los Angeles Angels of Anaheim as a draft-and-follow pick in the 3rd round of the 2005 amateur draft. After one year of junior college, he was signed by scout Tim Corcoran for $500,000 and made his pro debut in 2006.
O'Sullivan won his major league debut, pitching for the Los Angeles Angels of Anaheim against the San Francisco Giants on June 16, 2009. He gave up one earned run in 7 innings, striking out 5 and walking one in an 8-1 victory on "Irish Heritage Night" in San Francisco. He had been called up earlier that day to replace an ailing Ervin Santana, then was sent down after the game to make room for reliever Rafael Rodriguez. O'Sullivan had started the 2009 season at AA Arkansas, then was promoted to AAA Salt Lake City where he was 5-2 in 10 starts at the time of his call-up.
In 2010, O'Sullivan made his first of the season for the Angels on July 20 and went six innings at Yankee Stadium, giving up only two hits and two runs in win over the Yankees. Two days later he was traded with minor leaguer Will Smith to the Kansas City Royals for former Angel farmhand Alberto Callaspo.
O'Sullivan's brother, Ryan O'Sullivan, has played in the minors since 2011.