Six weeks ago, McGregor suffered three broken ribs and internal bleeding in a nasty collision against West Ham United.
"I went the hospital the day after the incident at West Ham and I saw Allan in the intensive care unit," recalled Bruce yesterday.
"He was in a bad way and the doctors had come in and said that, hopefully, the next 24 hours will be okay because they would be crucial. There was a spell when we thought that he could lose his kidney.
"I think I have got this medically correct, but had the tear been just a bit more, there would not have been any way to stop the bleeding.
"In that situation, you can't repair it because you can't stop the bleeding, so you have to remove it.
"Those first 24 hours were crucial but then, McGregor being McGregor, he told me that everything was going to be all right in six weeks.
"I said: 'That's good'. He said: 'Yes because the FA Cup Final is going to be seven weeks away'.
"In his mind from that day in the hospital bed, he was convinced he was going to try and make it.
"To be honest, I just walked out of the hospital after that and thought: 'You are mad'.
"But then again, he is mad. Mad in a good way. Tough.
"Allan is a bit of a throwback to the old ones. He's a bit like (Hull midfielder) David Meyler in the sense you need a shovel to break their backs.
"He has given himself every chance and I did not think that day in the hospital there was going to be any chance."
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