Former England international forward Dean Ashton believes Sunderland's play-off hopes rest on the fitness of Aiden McGeady.
McGeady , 33, has enjoyed a stellar campaign scoring 14 goals and registering six assists in all competitions this season.
The Republic of Ireland international was also nominated for the League One Player of the Year award but missed four of the final eight games of the season due to injury.
Sunderland won just two games during that period allowing automatic promotion to slip from their grasp.
Jack Ross' side ended the campaign in fifth place and must now win through the end of season play-offs to secure Championship football next term.
The Black Cats take on Portsmouth in their two-legged semi-final and will face either Charlton or Doncaster in the final at Wembley if they can see off Pompey.
But should McGeady not return to the side during that time, Ashton holds little hope for Sunderland returning to the second tier at the first time of asking.
“They won’t get promoted without him, it’s as simple as that," Ashton told Football League World.
"He’s that important. Having watched him a lot this season, he’s by far the standout in that team, and he’s far too good for the level they’re currently at.
“You’d arguably say at times that he’s too good for the Championship, so they’ve got an unbelievable player still there and he’s shown it this season.
“But without him, I just don’t see them having that cutting edge to get promoted and Sunderland have already slipped up recently. It would be a huge blow to not have him available for the play-offs.
“If they don’t get promoted this season, I’d be amazed if he stayed on with the club as there will be lots of clubs looking at him in the summer.”
Sunderland welcome Portsmouth to the Stadium of Light on Saturday for the first leg of their League One play-off semi-final. The action gets under way at 7:30pm.
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