Stewart, a 6-foot-7 redshirt junior, did not play in the last five games coached by Kevin O’Neill but was becoming a regular part of the rotation under interim coach Bob Cantu.
The injury occurred in the second half Sunday when a Husky player tried to steal the ball. Stewart grabbed the hand immediately.
Stewart is averaging 3.6 points. He is in his first year at USC after transferring from Wake Forest. He has the fourth-most assists for the Trojans.
The Trojans (10-13, 5-5) are in the midst of their first three-game winning streak of the season and are in a four-way tie for fifth place in the Pac-12 Conference. They travel to Stanford on Thursday and California on Sunday. Stanford and California are also tied for fifth.