Pogba and Fernandes started in the 0-0 draw against Liverpool on Sunday and were again on the team-sheet in Manchester United’s 2-1 win over Burnley in midweek.
With Manchester United in the thick of the title race, there are suggestions Ole Gunnar Solskjaer could rotate against Liverpool at Old Trafford in order to keep his big names fresh for the league campaign.
However, Mellor stressed that he would be shocked if all of Manchester United’s big names are not in the starting eleven when the teams are announced on Sunday.
He believes Manchester United could easily rotate against Sheffield United next week in the league and feels all their big names will be on the pitch from the start against Liverpool in the fourth round of the FA Cup.
Mellor said on LFC TV: “I would be amazed if Manchester United do not play their best players for this game.
“Pogba, Fernandes, [Harry] Maguire and [Marcus] Rashford didn’t play in the last round but I expect all of them to play.
“If you look at their midweek Premier League game, it is Sheffield United at home so that they can go all out for this one.
“I expect a very strong line-up, I’d be amazed if Fernandes does not start this game.”
Liverpool have not beaten Manchester United in an FA Cup tie at Old Trafford since the 1920/21 season.