McGill was listed as the top tailback on this year's preseason depth chart.
"I'm extremely disappointed for Ronnie," John Bunting said in a later UNC release. "He is an exceptional person, a tremendous team player and a great representative of this University. I know he will work hard to rejoin his teammates on the field as soon as he can."
McGill played in seven games last season and finished third on the team with
419 yards rushing on 79 carries. He scored five touchdowns and averaged 5.3 yards per carry.
He began the season as the starting tailback, but injured his ankle against Georgia Tech and missed five games.
As a true freshman in 2003, McGill played in 12 games and started eight, leading the team with 654 yards on 128 carries. He scored seven touchdowns that season and was seventh in the ACC in rushing yards per game (54.5).
LSU transfer Barrrington Edwards, who has never played a down at UNC, will likely now move into the starter's slot.
UNC Athletic Communications contributed to this report.