Both players featured in United’s opening two defeats to Brighton and Brentford with Ronaldo still seeking a move away from Old Trafford, while Rashford hasn’t scored a league goal since January.
United suffered 5-0 and 4-0 thrashings against Liverpool last season and Rooney wants Ten Hag to leave out the two forwards in order to match Jurgen Klopp side’s intensity levels.
“I wouldn’t play Cristiano Ronaldo, and I wouldn’t play Marcus Rashford [against Liverpool],” Rooney wrote in his Sunday Times column.
“If I was in Ten Hag’s position my main concern would be getting energy on the pitch, and United’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.
“He has also let it be known that he wants to leave the club. I don’t know his reasons but, as I wrote in my last column, I’d let him — he’s a great player and will always score goals but the task for Ten Hag is to produce a team that can compete for the title in three or four years’ time. That means rebuilding with younger players.
“As for Marcus, I think he needs to do a lot of soul-searching and figure out what he wants, for his own good, before anything else. Because watching him is a real concern: He looks like he wants to be anywhere but on a football pitch.
“I haven’t seen him smile on the field for a long time. His performances have dipped — he hasn’t been selected by England for more than a year. I’m coming from a place of wanting the best for him. He’s a lovely kid and a local lad who came through the ranks at United, who everyone wants to see doing well.
“But you look at the difference between Marcus now and when he first came into the team: the passion he showed, the smile on his face when he scored. It’s night and day.”
“Casemiro, United’s new signing, will not be eligible to face Liverpool, which is a pity because he will undoubtedly improve United,” Rooney added. “He’s a good player. I’ve played against him and he’ll bring a bit of character, a bit of work rate, but is he exactly what United need? I’m not sure.
“This goes back to the need to look to the future. Ideally, they should be signing players in their early to mid-twenties, and Casemiro is similar to Christian Eriksen — someone who has been a good player, but are they going to help the club move forward? Frenkie de Jong, Ten Hag’s principal midfield target, would be a better fit.
“The Casemiro deal seems to have come from nowhere, and looks a reactive signing — I’d be surprised if he was a player identified as a priority to bring in when Ten Hag arrived. It looks like, having been unable to sign De Jong, United just reacted to Casemiro being available.”