Fisher’s injury occurred during Tuesday’s practice.
Fisher is the starting point guard for the 13-4 Horned Frogs, averaging 12.3 points and 5.4 assists. Over his last four games, Fisher has put up 16.3 points and 4.3 assists, including a 22-point effort in a loss to Oklahoma on Saturday.
TCU has lost four of five in Big 12 play, after starting the season 12-0.
Without Fisher, expect guard Alex Robinson (7.4 PPG, 4.9 APG) to see more time on the ball. Jamie Dixon is also likely to use a bigger lineup that features 6-foot-5 Desmond Bane (12.1 PPG) and 6-foot-7 Kouat Noi (9.1 PPG) on the wings.
TCU hosts Iowa State on Wednesday.