The 22-year old has been left unprotected by the Union and Impact head coach Jesse Marsch has confirmed they will look at adding him to their inaugural MLS squad if they feel he is the right player to come to Montreal.
"We're analyzing how Freddy would fit," Marsch said. "We know him.
"Mike (Impact assistant coach Sorber) and I both know from working with him with the (U.S.) national team, so we're just trying to figure what that would be like and how it would fit, what Freddy's interest level is and everything else.
"It's a surprising name though, that's for sure."
Adu returned to MLS in August after about four years in Europe and scored two goals in 11 appearances for the Union.