Stuttgart managed to beat Rangers in Glasgow on Tuesday, but Hleb was left highly impressed by McGregor.
He said: “If it hadn’t been for the Rangers goalkeeper maybe we could have scored five.
“McGregor played very well.
“I know there are a lot of Scottish players in the Premiership right now and good keepers like this will always have the chance to go there.
“He could certainly play for a team of the quality of Manchester City or Manchester United.”