Rose injured his knee while going up for a layup with 1:21 remaining in the Bulls' 103-91 win. An MRI taken at a local hospital showed the extent of the injury.
The Bulls played very well in Rose's absence this season; Rose missed 27 games due to a variety of injuries, but the Bulls still posted the league's best overall record. C.J. Watson will likely move into the starting lineup for the remainder of the playoffs, with John Lucas taking over as backup.
That alignment should still be enough to get Chicago past the Sixers, but a second-round date with the Celtics or Hawks looms.
The injury will almost certainly eliminate Rose from consideration for the 2012 Olympic team as well.