The Red Devils are still trying to bring consistency out of an £89 million asset, with it hoped that his World Cup-winning exploits with France over the summer would carry over into the new Premier League season.
Pogba has delivered flashes of brilliance in 2018-19, with a stunning goal netted in his most recent Champions League outing against Young Boys , but he has as many critics as he does supporters.
Souness sits in the first of those categories, with the Liverpool legend having often aired outspoken opinions on the flamboyant 25-year-old .
The Scot has now suggested that Pogba remains too individualistic to be one of the best in the business, with more professional performers such as Milner showing him how things should be done.
Asked by Paddy Power to make a selection between rival performers at Old Trafford and Anfield, Souness said: “That’s easy.
“It isn’t even a question. Milner, every day of the week. He’s a proper player.
“Who would I rather play against? Paul Pogba. I don’t want to play against Milner.
“But, with Pogba, it’s all about him and his game. He’s not going to stop me, he lets you play, and that’s one of the criticisms.
“Having the ball is only half of the game. A big part of being a top player, as he aspires to be, is you have to stop the guy you’re up against.
“And that’s part of the captaincy. If I’m having a good day, that means I’m stopping the guy I’m against directly.
“It’s not just about I’ll play and I’ll play, there’s another side to the game.
“You can’t pick and choose when you want to be bang at it.”
Pogba’s ability to divide opinion is reported to have put pressure on his working relationship with United manager Jose Mourinho .
Souness is not surprised by the talk of rifts at Old Trafford, with it “criminal” that a player of such potential has been unable to fully unlock it.
He added: “I’m a bit like I’d imagine Mourinho is, where you see someone who’s got so much talent, but not making the most of it.
“There’s a player in there, but I don’t think he’s getting the most out of himself. It’s criminal.
“I think he has to change. The guy who works with him every day is not seeing eye-to-eye with him, so he’s happy with him.
“I imagine he’d see it exactly the same way that I would: you’ve got a young man who’s got the potential to be the very best of his type in the game, but right now it’s not happening for him.
“With him, he needs to sit down and look at himself if he wants to get where he wants to be.”