(AP) _ Cavaliers guard Daniel Gibson has separated his left shoulder and will miss Cleveland's Game 6 against the Boston Celtics.

Gibson, one of the Cavs' best perimeter shooters, left in pain early in the fourth quarter Wednesday night following a collision and did not return.

The team said an MRI revealed a first-degree separation and estimated he would miss one or two weeks.

The Cavaliers trail 3-2 in the best-of-seven series and face possible elimination on Friday night. They'll miss Gibson, who emerged as a star Game 6 of last year's Eastern Conference finals when he made five 3-pointers and scored 31 points _ 25 in the second half _ as the Cavaliers closed out the Detroit Pistons.