Manly have been rocked by the late withdrawals of back-rowers Glenn Stewart and Anthony Watmough for today's blockbuster against the Roosters at Sydney Football Stadium.

The setbacks came as former international forward and club scout Noel Cleal called for both players to be included in Australia's squad for the World Cup.

"He's as good as any second-rower getting around right now," Cleal said of Stewart.

"I don't say that because he plays for Manly but if you look right across the board, he and 'Choc' [Watmough] are in the form three or four back-rowers playing today. He plays without any fanfare and stays away from any limelight, but people are starting to see what he does. His one-on-one stuff is just about the best in the game.

"He's 105 kilograms, he played five-eighth in the under 20s so he's got outstanding footwork.

"He asks a lot of questions on his own. Other players need assistance to get their nose through the line. He can do it himself."

Stewart (shoulder) and Watmough (knee) were ruled out yesterday. Stewart had carried his injury for a month while Watmough, soldiering on with an ankle problem, suffered a heavy knock to his knee last weekend.

They won't get the chance to boost their World Cup claims against the Roosters' representative back-rowers Willie Mason, Craig Fitzgibbon and Anthony Tupou this afternoon.

"I will be very, very surprised if Glenn doesn't make the squad for the World Cup," Cleal said.

"He will be in it. I know the respect that he has from the other players at other clubs. I talk to a lot of players in the NRL because of my affiliation with a lot of different players.

"He's highly rated. His peers are some of his biggest fans. There is a lot of respect for him, not just from the Manly club, but from a lot of other players and coaches I've spoken to.

"He would be highlighted more than people think in a lot of planning done by clubs playing against Manly."