A school spokesman told ESPN that Wallace suffered the injury Saturday in practice.
The 6-foot-5 Wallace leads the team in scoring (15.4) and assists (4.6) and is averaging 5.1 rebounds per game. He will be replaced in the starting lineup by reserve Sam Singer, who is averaging 4.1 points and 2.0 assists in 19 minutes per game this season.
However, Cuonzo Martin's team has struggled and is 12-6 overall and 2-3 in Pac-12 play. The Bears are in a four-way tie for seventh in the league and will face Arizona State on Thursday in Berkeley.