Drafted by the Houston Astros in the 2nd round of the 1970 amateur draft (Secondary Phase). Major league debut was on September 10, 1972. Final game was with Houston on September 25, 1976.
Originally drafted by the Reds in 1969 but did not sign. In 1989, Cosgrove played for the Orlando Juice of the Senior Professional Baseball Association. In 1990 he pitched 4 games in the Senior Professional Baseball Association for the Florida Tropics. It appears Cosgrove played three games this past summer with the Orange County Flyers of the Golden Baseball League.