Cosgrove appeared in seven games in 1972, going 0-1 with a 4.61 earned run average over 13.2 innings of work as a 21-year-old.
His best year would easily be 1974 when he posted a record of 7-3 with a 3.50 ERA over 45 appearances, with two saves and 47 strikeouts in 90 innings.
He would go on to pitch five years in the Big Leagues, all for the Astros, ending up with a career record of 12-11 over 119 appearances, all but 20 of those out of the bullpen, with a 4.03 ERA in 274.2 innings pitched between 1972 and 1976.