Michael A. Costanzo
- Bats Left, Throws Right
- Height 6' 3", Weight 215 lb.
- School Coastal Carolina University
- Debut May 13, 2012
- Final Game June 5, 2012
- Born September 9, 1983 in Philadelphia, PA USA
Third baseman Michael Costanzo was selected by the Philadelphia Phillies in the second round of the 2005 amateur draft. He was signed by scout Roy Tanner and made his pro debut that summer with the Batavia Muckdogs, where he hit .274 with 11 homers and 50 RBIs. He spent the next season with the Clearwater Threshers, with whom he hit .258 with 14 home runs and 81 RBI. In 2007, he played for the Reading Phillies and hit .270 with 27 homers and 86 RBI. As of 2007, he had led his team in home runs in every stop in the minor leagues.
Following the 2007 season, Contanzo was traded with two other players to the Houston Astros for Brad Lidge and Eric Bruntlett. About a month later, he was subsequently sent to the Baltimore Orioles along with four other players for Miguel Tejada.