It is a far cry from last term when the 25-year-old netted 30 goals in all competitions, including the winner in the corresponding Premier League fixture against City.
Walker said: “I think Marcus has shown over the years that he’s the sort of player who can create problems for any side if they don’t match him.
“He’s been important for both United and England since he was a teenager because of the threat he offers to any team he’s in. He’s got a lot of different qualities and we know he can be dangerous at the weekend.”
Rashford’s decisive 82nd-minute strike on City’s last trip across town in January capped a controversial fightback by the home side.
United had cancelled out Jack Grealish’s opener just four minutes earlier through Bruno Fernandes despite Rashford having been in an offside position during the build-up.
After bouncing back spectacularly by winning the treble – and beating United in the FA Cup final – Walker insists City are not motivated by revenge.
“I don’t think we think like that,” said the right-back. “Last season is done, we lost at Old Trafford and went on to win the treble. Ultimately that’s what matters.
“Of course this game means a lot but it’s part of a bigger picture and, OK we lost last season and the luck didn’t go in our favour, but we bounced back from that and did what we did.
“We want to win the game because of what it means and because ultimately it will help us in trying to win the Premier League again. We don’t need to think beyond that.
“We’ve had some great games against them in recent years and our focus is on giving the fans something to enjoy again on Sunday.”
City are in a strong position despite a blip before the recent international break, when they lost to Wolves and Arsenal, and lacking the intensity they showed at the end of last season.
Walker said: “People keep saying how hard it must be to get motivated because of what we achieved last season but we’re all competitors who want to win. We’ve shown that year after year.
“If it was hard to get motivated then we wouldn’t have won three Premier Leagues in a row.
“We go into every game wanting to win, for ourselves, for this club and it’s the reason we’ve been so successful. That doesn’t go away just because we did something special last season.”
Join our commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies