The school announced the personnel change just before tipoff in Tuscaloosa.
Losing Sexton didn't hold back the Tide, however, as Alabama ended the Tigers' 14-game winning streak with a 76-71 victory.
Sexton, a 6-foot-3 freshman from Georgia, leads the team in both points (19.3) and assists (3.4) per game while also adding 3.6 rebounds a night.
With Sexton out, fellow freshman John Petty led the way for the Crimson Tide, scoring a game-high 27 points.
Alabama coach Avery Johnson said Sexton is "day-to-day" after being injured midway through Monday's practice.