Farmer had been facing an undisclosed eligibility issue from the NCAA that threatened his ability to play this season.
Farmer, a redshirt senior, is North Carolina's lone returning starter on the defensive line. He totaled 30 tackles and 2.5 tackles for loss last season.
North Carolina announced Wednesday night that four players were suspended for the season opener, reportedly for an alleged hazing incident, including starting cornerbacks Desmond Lawrence and Brian Walker.
The Tar Heels open the season Saturday against Liberty.
- Ben Estes