Harrison Barnes nursing ankle injury

North Carolina coach Roy Williams is hoping Harrison Barnes will be able to play when the fifth-ranked Tar Heels face Wisconsin (No. 7 ESPN/USA Today, No. 9 AP) in the ACC/Big Ten Challenge on Wednesday.

"If we had a game today, he would not have played," Williams said during his Monday night radio show, adding that Barnes was held out of practice earlier in the day.

Barnes, the team's leading scorer and a preseason All-American, rolled his ankle while scrambling on the sideline for a loose ball during UNC's 90-80 loss Saturday to UNLV in the Las Vegas Invitational title game.

He immediately flashed the tired signal and went to the bench. Although Barnes waived off the trainer, he had a towel over his head for several minutes before eventually returning to the game.

Barnes left Orleans Arena on crutches. A team spokesman said at the time that the move was a precautionary measure. On Sunday morning when the team left Las Vegas, the crutches were gone.

The ACC Preseason Player of the Year made only 6 of 16 shots during the Tar Heels' first loss of the season, finishing with 15 points and five rebounds. He's averaging a team-leading 17.3 points to go along with 4.8 rebounds this season.

If Barnes cannot play, sophomore Reggie Bullock and freshman P.J. Hairston will have to play more minutes and pick up the slack, Williams said.

Bullock is averaging 7.8 points per game, while Hairston is averaging 9.7.

Robbi Pickeral covers North Carolina for ESPN.com and can be reached at bylinerp@gmail.com. Follow Robbi on Twitter: @bylinerp