Shaun Edwards admits London Wasps' season hinges on the next four games, starting with Sunday's Guinness Premiership clash against arch-rivals Harlequins.

The Wasps head coach needs all of his internationals available but revealed Tom Palmer will see a specialist on Monday which could lead to shoulder surgery ruling the England lock out for the duration of the up-coming Six Nations campaign.

Palmer sits out the Quins game at Adams Park, along with flanker Joe Worsley, who has a broken hand, and centre Josh Lewsey, whose hamstring is causing concern.

Prop Tim Payne is rested under the England Elite Player Squad regulations with Tom French taking over in the front of the pack.

After taking on Quins, Wasps are away to league Bath and follow that with a Heineken Cup pool game against Leinster at Twickenham and then another European clash at Castres.

Edwards's team are ninth in the Premiership and given their injury problems - captain Rafael Ibanez is also out for at least three weeks - and on-going contract negotiations involving England stars Danny Cipriani, Palmer, Riki Flutey and James Haskell, this is a dangerous time for the club.

That is why Edwards is warning his side that they are about to enter a pivotal moment of their campaign.

He said: "Our season will be dictated by the two Premiership fixtures and the two Heineken Cup games coming up and that is why we have to make a major statement.

"These four fixtures are absolutely vital and while we have been in this kind of position before and come through strongly in previous years, we don't plan it this way"

Having recorded an outstanding Cup double over Stade Francais and fashioned a last gasp 26-26 draw with Leicester, Quins have become a dangerous unit under the direction of All Blacks No10 Nick Evans.

Edwards rates Evans highly and believes the battle with Cipriani, the Wasps No10, will be something to savour.

He said "We are going to see the two fastest No10s in English rugby up against each other in this match.

"They both have searing pace and it is clear to see why Evans was pushing Dan Carter so hard for the All Blacks outside-half position.

"The more pressure he is put under, the more times Evans comes up with the goods and we have seen that in recent weeks and he has added another dimension to Quins' play."

Quins are able to field all of their England players, having rested Danny Care two weeks ago to satisfy the EPS agreement.

Nick Easter and Ugo Monye are not covered by the rules as they were added to the England squad from outside the 32 EPS players named by Martin Johnson, the team manager, at the start of the season.

Saracens have to rest England captain Steve Borthwick at Gloucester tomorrow with Eddie Jones, the club's director of rugby, demanding other experienced players step up to the plate in the lock's absence.

London Irish went into Christmas on top of the Premiership but faltered at Sarries with a performance which saw Toby Booth, their director of rugby, question their consistency.

It is now up to captain Bob Casey and his men to respond at home to Newcastle tomorrow.

The North East side are trying to stay off the bottom of the league and the rest of this season will be spent battling it out with Bristol, the worst team in the Premiership.