Carragher also questioned the signing of Donny Van de Beek, with the Dutch midfielder struggling for opportunities since his £35.7m move from Ajax.
“I actually admire (Ole Gunnar) Solskjaer for putting Pogba on the bench,” Carragher said on Monday Night Football on Sky Sports. "I said a few weeks ago after the Crystal Palace game, Fernandes and Pogba is not a midfield that can play together and never will be.
"Van de Beek, I don't understand the signing, I really don't get it, how he was ever going to play or where he's going to fit in.
"As soon as he signed I thought he plays No 10, Fernandes plays there, Pogba can play there.
"It's actually better for the team having Fred and McTominay in there. But having Fred and McTominay is not good enough for Manchester United to win the league either.
“The problem for me is Paul Pogba, I've said it for a long time. I'm with Gary Neville, Fernandes is the man for that No 10 position but I don't know how Ole can not pick a £90m signing in Pogba, it's difficult for a manager, so at some stage he will get back into the team.”
Gary Neville insists it is too early to categorically dismiss the potential for a midfield involving the pair.
“Ole's had six months to get Pogba and Fernandes together,” Neville said. "I don't think they've been in the position where they've played together that much so we can write it off already.
"If United's results don't improve with them both in the team then fair enough, but it's too early.
"Bruno, when he's with Fred and McTominay, when they play together they haven't lost a game. I think Ole's looked at it this week and said let's get back to basics, I know these three can play together.
“We were a mess pre-international break giving up chances left, right and centre. Beaten 6-1 at home by Tottenham, lost to Crystal Palace who looked comfortable, Brighton away we were fortunate. He's thought we need to get a foundation and he's done that with those three players in midfield.”