Reports have suggested that the LA Galaxy star will exercise a clause in his MLS contract to become co-owner of a franchise by buying into the Cosmos who are seeking the 20th license to play in North America's top flight.
However, Garber has made it clear that Beckham has been excused from edging his way into the prospective New York outfit which could join Eastern Conference giants Red Bulls in the competition.
"Anything's a possibility other than his right to exercise that option in New York," Garber told reporters.
"Major League Soccer has been looking at the possibility of expanding in New York since the league was founded in '96.
"There was a concept of having two teams in the league way back then. We knew when we were speaking with David and [Beckham's agent] Simon Fuller that eventually we would have an opportunity in New York regardless of the role that David played in helping grow the league."