ATLANTA -- Atlanta Hawks rookie forward John Collins is expected to be out two to three weeks with an AC join sprain injury he suffered on Thursday night, the team announced on Friday.

Collins injured his left shoulder during the Hawks' 121-114 loss to the Cleveland Cavaliers at Philips Arena.

The rookie has shown a lot of potential, showing off his vertical during show-stopping dunks in his first games since getting drafted No. 19 overall last summer out of Wake Forest.

He is averaging 11.5 points per game and 7.1 rebounds.