McGeady has been made to pay dearly for the pair's bust-up in the wake of the 1-1 Clydesdale Bank Premier League draw with Hearts, with the player also fined two weeks' wages for what has been described as "a breach of club discipline".

The Republic of Ireland international is thought to have reacted badly to a dressing-room dressing-down from Strachan after Saturday's match.

But rather than accept his punishment, it appears the 22-year-old remains defiant.

Agent David Holbrook, who yesterday claimed he knew nothing about the disagreement, told BBC Sport: "I can confirm that Aiden has been fined by the club and suspended. He's shocked, disappointed - and I can say he will be appealing.

"He feels that the action is completely unjustified."

It is a brave decision by Strachan, given that he is effectively banning his star player from the derby trip to Rangers on December 27.

But the Hoops boss has received the backing of his club's board, with Celtic saying in a statement: "Following a breach of club discipline, Celtic manager Gordon Strachan has suspended Aiden McGeady from training with the first team for two weeks and has fined the player two weeks' wages.

"Gordon's decision has the full support of the Celtic board of directors."

Holbrook reports McGeady is upset at missing the Old Firm derby, adding: "He wants to play in that game and every Celtic game.

"He remains 110% Celtic; he's supported them, trained with them and loves them.

"But there's a difference between how Aiden feels he's been treated by the club's hierarchy, as opposed to his relationship with the club at large."

Saturday was not the first time McGeady and Strachan have reportedly clashed, with rumours of a confrontation following the August 31 Old Firm defeat.

McGeady subsequently found his first-team opportunities limited, although he was eventually restored to the starting XI.

The 22-year-old had only recently returned to the team following a month out injured and was in goalscoring form in Wednesday's Champions League win over Villarreal.

But he was one of a number of players to put in a below-par performance against Hearts, with the culprits all feeling Strachan's wrath.

McGeady is thought to have been the only one to question his treatment, casting further doubt over his future at Parkhead.

He was the undoubted star of Celtic's SPL title triumph last season, winning both the SPFA Player of the Year and Young Player of the Year awards.

But he has struggled to recapture that form this term, leading to speculation he could be sold - especially with the club today signing Derry City winger Niall McGinn.

Former Celtic striker Frank McGarvey told PA Sport: "I think it is the beginning of the end for McGeady - I don't see any way back for him now.

"The situation is even more serious than most people thought. There must have been some harsh, harsh words said - and if it could be rectified then it would have been rectified by now.

"It is obvious that they don't get on well, and what McGeady said was probably borne out of frustration.

"There is no long-term future for him under Strachan, so the best thing Celtic can do is sell him in the January transfer window.

"There will be plenty of clubs interested in him, and Celtic will get a good fee and then everyone can move on.

"In this situation, there is only going to be one winner - and that's Strachan.

"I was shocked by the news. But Strachan has to have discipline, and I understand why he acted the way he did.

"If there is no discipline in the dressing room then all the other players will think they can get away with the same thing - and that is not healthy.

"It is a big gamble but it is a gamble that has to be taken."

Lisbon Lion Tommy Gemmell urged McGeady to take his medicine, saying: "There is a management team in charge - Aiden McGeady is not in charge.

"They have rules for players for on and off the park.

"It will dissuade other players from doing the same thing. Now Aiden has got to take his punishment.

"He's still a young man, so maybe it's a lesson learned for the future.

"If he has the guts and the backbone then he will take his punishment and then come back - but if he doesn't then he might have to think about moving.

"We had lots of bust-ups under big Jock (Stein), but they were always seven-day wonders.

"Most of the Lisbon Lions at one time or another would have an argument with him after a game or at training. But it was always thrashed out, and we moved on."