Pogba - who also returned to United five years ago after leaving for free in 2012- says it if beneficial for the squad to train with a 'great player'.
The French midfielder told Telefoot, via Get Football News France: 'It's always a pleasure to play with the best.
It's also a plus for the players to be able to train with a great player. He's going to raise the level of the team.'
Speaking previously to Sky Sports, Pogba also said that Ronaldo's 'experience' would help point Ole Gunnar Solskjaer's men in the right direction for the 2021-2022 season.
He said: 'Everybody knows [what Ronaldo brings]. He's already a legend in this club and he's coming back, so obviously it's huge for us, for the club.