John McCahill is another of the NHL's One Game Wonders, getting his one shot at hockey glory in 1977-78 with the Colorado Rockies. He signed a free agent contract with the team on March 18, 1978 and was called up to fill in as an injury replacement.
McCahill had played four years in the NCAA with the University of Michigan. He also played a handful of games in the CHL with the Tulsa Oilers. He also played with the Fort Worth Texans and Oklahoma City Stars.
After spending a year with the Muskegon Mohawks of the IHL, McCahill decided to retire at the young age of 25. It was apparent he was highly unlikely to gain a regular spot in the NHL and rather than toil in the minors, he opted to leave competitive hockey.