Allan is set for a return to Parkhead as an opposition player after joining Hibernian this past summer.
The 28-year-old midfielder officially joined the Easter Road club in January under now-Celtic boss Neil Lennon but only officially arrived in June.
Since leaving the Hoops, the Scot has proven himself an excellent midfielder and has caught the eye with a series of defence-splitting balls.
The Glasgow-born star only managed 382 minutes of Premiership football for Celtic despite signing on in 2015.
And McGregor has warned his team-mates that they'll need to keep an eye on him today.
He told The Scottish Sun: "I think everyone knows Scotty has got ability and you can tell when you watch him. You see the pass he made at the weekend. That is the type of player that he is. He always likes to play that killer pass.
"He would play passes in training and you would think, ‘How did he get that through?’."
Talent as a stand-alone quality doesn't mean much if you don't have other qualities to make your ability flourish.
And it seemed like Allan, despite having a natural knack for midfield play, simply lacked other aspects which saw him become something of an also-ran under Brendan Rodgers.
Lennon is obviously a fan, hence why he signed him for Hibs, but the good news is that the Northern Irishman should know his game well enough to combat him.
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