County manager Jim McGuinness watched in horror as the match between Glenswilly and Naomh Conaill in Glenties ended in a fight.
The manager had wanted all games postponed at the weekend ahead of the Ulster Final clash with Derry.
Donegal disciplinary chiefs confirmed today a full investigation into the melee.
County secretary Aodh Mairtin O Fearraigh confirmed that the county’s Competitions Controls Committee will investigate the incident.
McLoone had scored a late goal but Glenswilly held on for a 1-10 to 2-6, which ended Naomh Conaill’s reign as county champions.
“The county’s Competitions Control Committee will be looking into it thoroughly, but I can’t say anything more than that on it at the moment,” O Fearraigh said.
McLoone suffered a double break in his eye socket and not a broken jaw as had been initially suspected, but he will miss the county’s first appearance in an Ulster final since 2006.
McLoone had only recently recovered form a broken ankle he picked up in March and he had featured off the bench against both Cavan and Tyrone in the Ulster championship, and he was believed to be pushing hard for inclusion from the start against the Oak Leaf.
The remainder of McGuinness’ squad came through their respective matches unscathed and they now go in search of their first Ulster championship title since 1992, when they went on to secure the county’s only All-Ireland success.