Erik ten Hag's side will take on their arch rivals Liverpool on Monday, August 22, with both teams hoping for their first Premier League win of the campaign.
The Red Devils have lost their first two games of the season while Liverpool have only managed two draws in their first two outings.
Rooney has claimed that he would have dropped both Ronaldo and Marcus Rashford against Jurgen Klopp's side.
Ronney has urged Ten Hag to get more energy on the pitch against their rivals by sacrificing the two attackers. The all-time top England scorer said, as quoted by UtdDistrict:
"Against Liverpool, I wouldn’t play Cristiano Ronaldo, and I wouldn’t play Marcus Rashford."
"If I was in Erik ten Hag’s position my main concern would be getting energy on the pitch."
Rooney has claimed that Ronaldo did not look match fit against Brentford on August 13, as Manchester United suffered a humiliating 4-0 loss.
The Englishman added:
"#mufc’s failure to recruit a No 9 means they relied on Ronaldo against Brentford, even though he hadn’t trained a lot with the team."
"He looked like he needs time to get match fit."
Ten Hag will demand a strong response from his Manchester United side including Ronaldo against Liverpool
Ten Hag started his tenure at Old Trafford in the worst possible fashion, having suffered two defeats in the first two league games.
The Red Devils looked pretty impressive under the Dutchman during their pre-season but have looked completely out of sorts since the start of the season.
The defeat against Brentford was preceded by a 1-2 loss at the hands of Brighton & Hove Albion on August 7 giving Ten Hag food for thought.
It will be quite interesting to see how the Red Devils line up against Liverpool on Monday but the chances of Ronaldo dropping out are quite remote.
Ten Hag has been boosted by Anthony Martial's return from a hamstring problem but the Frenchman is likely to be named on the bench.
Meanwhile, Rashford's chances of sitting out on the bench are also negligible as Manchester United do not have too many senior options on the flanks.
Regardless of the team he picks against Liverpool, the Dutch manager will surely demand a strong response after a dismal start to the campaign.