It was supposed to be Aston Villa's dream defensive partnership.

But Olof Mellberg and Martin Laursen have played together only six times this season and will probably have to wait until August to revive what looked like becoming a solid combination.

Mellberg's knee injury, which required surgery on Wednesday, is not serious but it will require at least six months of rehabiliation, meaning a premature end to his season.

The Villa captain remains optimistic - "I would hope to be back before the end of the season" - but time is running out and reality is setting in.

David O'Leary, the Villa manager, refuses to put a date on Mellberg's return, which is probably wise given that Darius Vassell and Gavin McCann were ruled out for the season but have made dramatic recoveries.

Mellberg's injury means that Liam Ridgewell, who deputised while Laursen spent six months out with a knee injury, will return to the starting line-up for the match against West Bromwich Albion on Sunday.

"The operation went well, or at least that is what the surgeon told me," Mellberg said. "The plan is that we take it very easy over the next seven to ten days and then pick it up from there.

"This sort of injury is usually around six weeks of rehabilitation. Six weeks would obviously mean the end of the season for me, so I would hope to be back well before then.

"It is very frustrating because I felt that we had something going both as a team and for me personally, especially as Martin Laursen is now back in the team and playing well.

"It seems unbelievable to think myself and Martin have started just six matches together all season."

Villa have denied speculation that Juan Pablo Angel, the Colombia international striker, has already been ruled out of the match against Albion on Sunday because of injury.

Angel is sure to start up front with Vassell while there could also be a place for Thomas Hitzlsperger, the Germany international midfield player, who will leave for VfB Stuttgart in June.

O'Leary has made it clear that Hitzlpserger remains an important member of the squad even if the player's Villa career, which began in 2000, is drawing to a close.

"I have no doubts in my mind that he [Hitzlpserger] will remain in the squad," O'Leary said. "I have had Tom in my office and told him that I am sorry to see him go. I told him 'I will pick you no matter what decision you have made because I do not want to cut my own throat'.

"I've seen a couple of quotes in the paper, blaming me for this or that, and I have told him he was totally wrong with what he said. The bottom line is that Tom is leaving and if it is not about money then he is leaving because he did not want to compete for places at this football club.

"If he checks the records, which he has not, he has played more games than most of the midfield players who have been here in the last couple of seasons. He has had a lot of games - more so than most of the midfielders at the club.

"The pull of going back to Germany was the big thing. That is the be-all, end-all; the bottom line of it.

"So why didn't he just say that? When he was talking contracts with the club it was all about 'I need to be playing because . . .' But why? Because of the World Cup 12 months on.

"Tom did not want to take his chance with us. I am going to try to build a bigger squad here for next season. So stand and fight for that. It has not done him any harm over the last 18 months."

* Villa are finalising a three-match pre-season tour of Sweden. The team will travel to Scandinavia in late July but the identity of the opponents have yet to be publicly revealed.