Nixon suffered the injury during Monday's practice at the Kohl Center. He wore a protective boot on his left foot while watching practice Tuesday.
If Nixon cannot play, sophomore guard Michael Flowers would take his place in the starting lineup and sophomore Tanner Bronson would be the primary true guard off the bench. Flowers has started twice and is third on the team in minutes, averaging 24.3 per game. The little-used Bronson has appeared in 16 games and played 49 minutes all season.
The Badgers are scheduled to have a two-hour practice at the Kohl Center today, prior to their departure for Philadelphia.
Each team with a first-round game at the Wachovia Center Friday will have a shootaround session Thursday that is open to the general public. The Badgers have the first slot, from noon to 12:40 p.m. Eastern. The team will then conduct a closed-door practice at Widener University.