The Scottish midfielder played no part in last Wednesday’s 0-0 draw with the Norwegian champions in their Champions League third qualifying round first leg clash.
Brendan Rodgers decided to go with other options, including Stuart Armstrong, Olivier Ntcham, Scott Brown and Tom Rogic in his starting XI.
But one of those players could find their place under threat after McGregor’s performance at the Stadium of Light.
He opened the scoring against Sunderland and went on to net his hat-trick before going off to a massive applause from the travelling support.
Now those fans believe he’s a certainty to start against Rosenborg on Wednesday:
Jonny Hayes got his first goal for the club in the first half and Stuart Armstrong climbed off the bench in the second half to help make it 5-0 to the visitors on a terrible day for Sunderland.
Celtic fans – would you start McGregor against Rosenborg?