While Wasps, who have lost their two opening Premiership games, were boosted by the news that Serge Betsen and ex-Saint Mark Robinson were fit to make their debuts for the club at Franklin's Gardens, Saints have been hit with the loss of in-form Clarke.

After a try-scoring start to the season, Clarke was being tipped for England honours by former British Lion Jeremy Guscott. But the 24-year-old limped off in the defeat to Newcastle on Sunday and has been ruled out of the Wasps clash with a hamstring problem.

Clarke was sent to see a specialist yesterday, and the seriousness of the injury is not yet known.

It is a blow to Saints, but Mallinder is confident in Joe Ansbro and summer-signing Chris Mayor he has got more than adequate replacements.

Ansbro, who has played for Cambridge University in the Varsity match, burst onto the scene in division one last season with a series of assured displays and Mallinder has picked out the 22-year-old as one for the future.

"Joe is a good player," said Mallinder. "He did well for us last year when Clarkey got injured towards the end of the season. He is defensively strong and he is quick, so we have got no hesitation in putting him or Chris Mayor into the team."

Mayor played the full 80 minutes for the Wanderers in their win over Bath United on Monday night and has the experience of winning a Premiership title with Sale.

Despite losing to Newcastle last Sunday, Mallinder says there is no need to panic and introduce mass changes to the side. Mallinder said: "We have got a good squad, and there were some really good performances from members of the Wanderers against Bath, so we have got players pushing for places.

"We are going to have a serious think and make sure that we pick the right team.

"Having said that it is important we don't panic. These players have played well against Worcester and in the first half against Newcastle, so there is no need to panic and take any drastic action."