Crusaders v Wolves: Teams

Mapp: Big loss

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Celtic Crusaders forward Darren Mapp has been ruled out for the season after having an operation to repair a torn pectoral muscle.

Mapp has been sidelined since the Super League victory over Wigan three weeks ago and has failed to respond to treatment.

Coach John Dixon said: "Darren was players' player of the year in both 2007 and 2008 and this alone shows how much he'll be missed."

Mapp has been a key player for the Crusaders, making 61 appearance in three seasons since joining from Cronulla Sharks, including 11 this season.

Utility player Marshall Chalk could be available for the first time since suffering a broken jaw against Castleford on April 26.

The former Canberra player may start at full-back although Dixon says he is not guaranteed to start.

"Marshall still has to go through some fitness tests," he said. "We won't know until Saturday whether he'll make this week's team. We'll have to make a balanced decision on him as we don't want to bring him back until he's thoroughly ready."

Matty Smith was named in last week's 19 but has been left out as he is still not fully recovered from an elbow injury.

Peter Lupton and Jason Chan are also named in the initial squad but neither is certain to play due to injury, which could leave Dixon strapped.

However, Luke Dyer and Chris Beasley could return after missing last week's trip to St Helens through injury.

Omission

Warrington are without Lee Briers (hamstring), Mickey Higham (bicep) and Paul Rauhihi (back for the trip to Brewery Field.

Rauhihi was a surprise omission from last week's squad against Hull FC and has not recovered in time.

Back rower Lee Mitchell comes into the 19 in his place while former Great Britain international Brian Carney is also in the running once again.

"Most have been to Wales in some shape or form but we've not been to the Brewery Field as a team so we look forward to that," said coach Tony Smith. "It will be a tough one. They gave us a tough run on our own turf so going into their back yard will be even more tough."

Crusaders 19-man squad:
Chris Beasley, Anthony Blackwood, Mark Bryant, Neil Budworth, Marshall Chalk, Jason Chan, Mark Dalle Cort, Luke Dyer, Ben Flower, Jordan James, Mark Lennon, Peter Lupton, Ryan O'Hara, Adam Peek, Damien Quinn, Steve Tyrer, Jace Van Dijk, Lloyd White, Lincoln Withers

Warrington 19-man squad:
Louis Anderson, Vinnie Anderson, Chris Bridge, Brian Carney, Garreth Carvell, Jon Clarke, Michael Cooper, Simon Grix, Ben Harrison, Chris Hicks, Paul Johnson, Matt King, Richie Mathers, Lee Mitchell, Michael Monaghan, Adrian Morley, Chris Riley, Ben Westwood, Paul Wood