Hughes initially was expected to be out six to eight weeks, but he said Thursday he might miss considerably less time after X-rays and an initial MRI showed no damage. Hughes said the shoulder was sore but not causing him any pain.

He got a dye injection for the second MRI, which provided a more thorough picture, and the team said Friday night he would miss two to four weeks.

Besides Hughes, the Bulls were without Ben Gordon (jammed left big toe) and Luol Deng (sore right toe, back stiffness) when they wrapped up the preseason against Milwaukee. That meant Gordon will have played in just one preseason game before the opener against the Bucks on Tuesday.

"It's a concern because he's not in game shape," Del Negro said. "Ben is a student of the game. He'll pick things up fast, but we hopefully can get him in two or three practices before Tuesday and get some good work in."

Bucks center Andrew Bogut has a sprained left ankle and wasn't with the team.