In October 1952 Cosgrove made national news as one of three Maryland players coming forward ahead of a game to expose attempted bribery in conjunction with a point shaving scandal.

His contract was traded to the expansion Baltimore Colts, who cut him at the end of training camp ahead of their debut 1953 season.

[2] The influx of older student-athletes back from military service in World War II had worked its way through college ranks, and younger players were expected to play a more impactful role on the varsity football squad in 1949, in the estimation of Baltimore Sun sports editor Paul Menton.

Cosgrove and Maryland quarterback Jack Scarbath were selected to play in the Senior Bowl in Mobile, Alabama, held January 3, 1953.

In October he became the subject of national news coverage as part of a bribery scandal in which he and two of his teammates went to authorities and informed them they had been offered cash to alter the result of a forthcoming game with Louisiana State University (LSU).

Cosgrove — a center who handled the ball on each offensive play[6] — asserted that he had been offered $1,000 for his part in the $1,500, three player scandal.

[11] Cosgrove got playing time during the team's preseason schedule but was waived from the Colts in the final cut to the league limit of 33 players on September 23.

[12] Cosgrove's situation is mentioned in the memoir of Colts lineman Art Donovan, who contends there was pressure on head coach Weeb Ewbank to keep Cosgrove on the Baltimore roster due to his roots at the neighboring University of Maryland despite Ewbank's desire to release him.

[13] "He was supposed to be an All-American but he really wasn't too good," Donovan recalled, "He was okay, not the best — he just had two great centers in front of him..."[13] In an exhibition game against Pittsburgh, Cosgrove suffered an ankle injury, Donovan contends, but instead of sitting him as the injury required, Ewbank intentionally inserted Cosgrove into a game so that he would look slow and incapable on film, thereby eliminating any potential front office objection to a controversial cut.