Ryan McHugh will miss the remainder of the Donegal's league campaign after it was confirmed that he had sustained ankle ligament damage in last Sunday's draw with Monaghan.
McHugh had the ankle placed in a protective boot after the game and a scan in Letterkenny on Wednesday confirmed that he will miss Sunday's final round league game against Mayo and a league final if Donegal make it that far the following weekend.
McHugh has had another impressive league campaign, grabbing his fourth goal against Dublin in four seasons and ripping Tyrone apart with pace and evasiveness in Ballybofey.
The Kilcar man is expected to be out for between three weeks and a month.
"I won't be available for Sunday although the injury is not as bad as I thought at first," he said. "I went over on my ankle in Ballyshannon and while it was painful at the time, it is improving fairly rapidly. I am getting about with the aid of a crutch but hopefully that won't be for too long.
"I had a scan on the ankle earlier this week and it seems that it is just a wee tear in a tendon."
Meanwhile, Donegal's Ulster U-21 semi-final with Cavan has been refixed for Enniskillen on Wednesday night next.
The match was originally cancelled last Wednesday because of a waterlogged pitch.
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Tyrone wont have the suspended Mattie Donnelly while defender Ronan McNamee is also out after breaking a bone in his hand as they prepare to head back to Killarney on Sunday.
Tyrone need to win and hope that Dublin and Mayo both oblige to give them a first Division One league final appearance in four years.
But their record against Kerry has deteriorated in this decade with just one win, a 2010 home league match, to show from six meetings.Their last trip to Killarney resulted in a heavy 3-15 to 0-9 defeat three years ago.
Padraig McNulty will replace Donnelly at midfield while Mickey O'Neill steps in for Niall Morgan in goals as the rotation policy continues.
Conal McCann comes into the attack for McNamee with Peter Harte dropping to defence in a reshuffle that sees Aidan McRory restored to corner-back and Padraig Hampsey switch to full-back.
Tyrone (SF v Kerry): M O'Neill; A McCrory, P Hampsey, C McCarron; T McCann, R McNabb, P Harte; C Cavanagh, P McNulty; C McCann, N Sludden, K McGeary; M Bradley, S Cavanagh, D McCurry.