Joe McMahon broke his jaw in two places and also had a number of teeth knocked out during a club game yesterday afternoon.
The versatile Tyrone player was lining out for Omagh St. Enda's in their All-County 'A' League opener against Moortown, when he sustained the injury in the first half.
The club website describes how he was 'felled during an incident which was not witnessed by the match officials.'
It is anticipated that he will be out of action for at least three months, which would rule him out of Tyrone's Ulster SFC title defence.
X-rays revealed that McMahon had broken his jaw and he underwent surgery last night to repair some of the damage in Derry's Altnagelvin Hospital.
A spokesman for St. Enda's said the club was shocked and angered by what happened on the opening day of the season.
Meanwhile, McMahon's Tyrone team-mate Enda McGinley sustained an injury and was carried off on a stretcher in Errigal Ciaran's league win over Cookstown.
Tyrone finished fourth in Division 2 of this season's Allianz Football League and are due to host Monaghan in a mouth-watering Ulster Championship quarter-final on June 5.