The former Anfield star believes Brendan Rodgers should stick with Dejan Lovren despite his poor showing against West Ham.
Both sides suffered demoralising defeats before the international break, with United being beaten 2-1 by Swansea City and Liverpool stunned 3-0 at home by West Ham United.
The Hammers reversal saw the Reds put in a torrid defensive display, with defender Dejan Lovren coming in for fierce criticism, but McManaman has urged Rodgers against making rash alterations - as a game against your fierce rivals isn’t the best platform on which to be mixing things up.
“Against Manchester United, I think you are taking a big chance if you start changing the team around,” he told the Independent.
"Lovren was fine against Arsenal, he was fine against Bournemouth, he was fine against Stoke. Yes, there were problems against West Ham but I wouldn't necessarily start changing the formation around for a game as difficult as Manchester United at Old Trafford.”
Chance for Ings or Firmino to impress
The Reds will be missing Philippe Coutinho for the game at Old Trafford, after the Brazilian was sent off in the shock defeat to the Hammers.
It is a big blow for Brendan Rodgers, with the midfielder having developed into the star man in Liverpool’s midfield over recent seasons, turning in a number of top performances - with his winning goal against Stoke on the opening weekend a clear indicator of that.
With the Samba star absent, McManaman says there is a chance for somebody else to step up and ignite Liverpool’s season, namely Danny Ings or Roberto Firmino.
"One player has to be a superstar at the weekend and ignite their respective team's season,” he added.
“It could be Danny Ings or Roberto Firmino for Liverpool, especially now that Philippe Coutinho is out of the side. If you ask Liverpool fans, Coutinho’s been the main man so far this season until his sending-off against West Ham. He'll be a big loss and somebody has to step up to the mark.”