Brown, who turns 34 in June, hasn't played for Celtic since October 20 due to injury.
In his stead, McGregor has done exceptionally well in what was originally an unfamiliar midfield role, and won a lot of praise for his display in the Hoops' 2-1 Europa League win over RB Leipzig on Thursday.
Brown has skippered Celtic to back-to-back trebles in recent years, and won a whole host of individual awards last season to remind Scottish football that he isn't slowing down in spite of the aging process.
And although Sutton acknowledges that the 25-year-old McGregor has been an excellent deputy, the former Bhoys hitman doesn't think that he'll keep the iconic Celtic star out of Brendan Rodgers's first XI in the long term.
Asked on BT Sport if Brown will 'walk straight back' into the team, Sutton said: "Yeah, I think he will. I think he's that valuable. I don't think people should start writing Scott Brown off, as well as McGregor has played.
"I don't think we should make McGregor out to be a world beater in that position. He's been very good but let's see over a long period of time [how he does]."
Sutton might well be right.
We live in a time when knee-jerk assessments are made by football fans, but Brown has been a monstrous influence on Celtic down the years and it'll take more than four or five good games to know definitively whether McGregor can be as influential in the long term.
He has been superb, but Brown isn't the type of character to relinquish his first-team spot easily.