GEELONG defender Tom Stewart has conceded to coach Chris Scott he made an error in elbowing Richmond's Dion Prestia and is now preparing for a lengthy stint on the sidelines.

Stewart is facing a long suspension for a first-quarter incident in Saturday's clash at the MCG that left Prestia concussed, and was subsequently subbed out of the game soon after.

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The triple premiership midfielder was dazed and confused after being collected by a forceful elbow from All-Australian Tom Stewart.

A groggy Prestia was helped off the ground by trainers and was replaced in the game by big man Ivan Soldo.

The incident will attract attention from the Match Review Officer and Stewart could be hit with a lengthy suspension.

He was booed by the Tigers faithful every time he went near the ball but still played a crucial role in the Cats' thrilling three-point victory, including taking a big contested mark near Richmond's goals in the dying seconds.

Scott went into detail about the chat he had with Stewart at quarter-time, and in the rooms after the game.

"I've known Tom for a long time and he is a scrupulously fair player and just a fantastic strong character, fundamental to what we do at Geelong," Scott said.

"When my time has come and gone, I'll look back and say I was honoured to coach Tom Stewart.

"When I spoke to him post-game, he said 'I've just made a horrible error and I feel terrible about it. I ran past the ball and I chose to bump, I didn't mean to do it but gee it was terrible execution and I'm going to pay the price for it'.

"I wouldn't normally be this expansive but I thought it speaks to the man.

"He knows he's done the wrong thing.

"Was it deliberate? Of course it wasn't. He's made an error, and as people do that I admire, he's prepared to stand up and say I was wrong.

"It doesn't help them ... they lose one of their best players and we don't run away from that fact.

"But he should have some comfort in the fact that's not him and it was an error of execution and nothing more.

"Tom's a pretty emotional guy and he was feeling it, we could see, visibly, it weighing heavily on him.

"He'll pay the price, I don't think there's much doubt about that, and you can't control what people think of you."

Richmond coach Damien Hardwick refused to buy into the incident but said Prestia was in decent spirits in the rooms.