Tyrone have pulled out of their All-Ireland SFC semi-final against Kerry next weekend due to a crippling Covid crisis in the camp.
The Red Hand decision throws the 2021 series into disarray and leaves the GAA with an unprecedented dilemma over its premier Gaelic football competition.
As it stands, Kerry will receive a bye to the final against either Dublin or Mayo, and Association chiefs now face a major decision over whether to offer the Ulster champions a further postponement.
Tyrone chairman Michael Kerr revealed in a statement this afternoon that the county would not be fulfilling next weekend's semi-final fixture against the Munster champions.
He said the decision has not been taken lightly, and was only made after consideration of expert medical advice.
The Ulster champions had requested a two-week postponement of their clash with the Kingdom due to a number of Covid cases in the squad.
But GAA chiefs granted just a six-day deferment, re-fixing the game for next Saturday, 21 August.
The GAA have since issued a short statement, saying they had received correspondence from Tyrone on the matter and intended to discuss the matter before making their response.
"The GAA can confirm it received correspondence from Tyrone today relating to their participation in next week's scheduled GAA Football semi- final," the statement read. "This correspondence will be discussed before any response is issued."
The GAA can confirm it received correspondence from Tyrone today relating to their participation in next week's scheduled GAA Football semi- final.— The GAA (@officialgaa) August 14, 2021
This correspondence will be discussed before any response is issued.
Kerr said concerns over player welfare are at the forefront of their handling of the situation, which left them with no option but to withdraw from the tie.
"This morning, the Tyrone GAA Management Committee has decided that it is not in a position to field its senior football team in the rescheduled All-Ireland football championship semi-final in Croke Park, on next Saturday," said the Tyrone GAA statement.
"Having received expert medical opinion on the existing, and future health and welfare of the players who contracted the Covid-19 virus during the period of this last two weeks, and following consultation with the team's management, this decision has been made with the greatest reluctance, and with deep regret.
"It is acknowledged that the decision taken will cause major disappointment and significant inconvenience for the Association, in general, the GAA fraternity of Kerry, and especially for Tyrone's patrons and supporters, but the welfare and safety of players has been the over-riding factor in all considerations of this difficult situation."
It is understood that some Tyrone players would still be unable to feature in the tie, even if it was put back for a further week, but that a large percentage of the squad would definitely be unavailable to play next weekend.
Tyrone have already been in such a position, and were without a number of players for the Ulster final two weeks ago due to Covid issues.
But they decided to go ahead with the Croke Park decider against Monaghan as they were still able to field an almost full-strength team.
Joint-manager Feargal Logan was one of those forced to remain at home due to the requirement to self-isolate, and the Red Hands emerged victorious to earn an All-Ireland semi-final place, but now face elimination from the race for the Sam Maguire Cup without kicking a ball.