He played in Major League Baseball (MLB) between 2000 and 2003 for the New York Mets, Houston Astros, and Pittsburgh Pirates.

During his senior year in 1992, Mann led the town's high school baseball team to an appearance in the Massachusetts Interscholastic Athletic Association (MIAA) tournament.

He subsequently attended Massasoit Community College and starred on the school's 1993 NJCAA Division II National Championship baseball team.

Mann was selected by the New York Mets in the 1999 Rule 5 draft, returned to the Blue Jays and then reacquired via trade in March 2000.

[citation needed] He made his major league debut in May of that year against the Los Angeles Dodgers.