McAdam wasn't given a qualifying offer, and will become a free agent, Christ Johnston from Sportsnet reports.
McAdam was assigned to AHL Toronto on Wednesday, New York Times contributor Dhiren Mahiban reports.
McAdam was called up from ECHL Newfoundland on an emergency basis Monday, Mark Masters of TSN reports.
McAdam was traded to Toronto in exchange for forward Matt Martin.
McAdam was assigned to AHL Bridgeport on Sunday.
McAdam signed a three-year entry-level contract with New York on Wednesday, Shannon Hogan of MSG Networks reports.