Martin O'Neill has hailed the contribution made by Aston Villa defender Olof Mellberg who will end his seven-year spell at the club in the summer when he joins Juventus.

The Sweden international has agreed a three-year deal with the Italian giants which will expire when he is 33.
Mellberg's current contract with Villa expires in the summer and it has been clear for some time that the £5million signing from Racing Santander in 2001 was considering a new challenge.

The only doubt was whether Mellberg would leave in January - after Juventus made an offer to Villa - or in the summer, and he has chosen the latter option.

O'Neill cannot fault the effort and commitment shown this season by Mellberg who has been played out of position at full-back.

He said: "Olof has made a big contribution at Villa and is a true professional, and that has been emphasised by the way he has performed this season at right-back.

"I moved him from centre-half, where he would prefer to play, and he has never once complained to me about having to play virtually every week to right-back.

"He was the only one of our defenders able to do that and I have greatly appreciated his efforts.  There has been a lot of talk about his future but he has been having a really good season.

"Last season, when we were topsy turvy, I thought he had plenty of consistency as well but that is the sort of player he is."

O'Neill added: "But if someone like Juventus shows an interest, and within six months of your contract running out, I think you have to explore every avenue.  He told me a while back that he wanted to have a look and see what was going to develop and I wish him all the best for the future.

"This is a very important time of his career. He has been here seven years and when you get clubs the size of Juventus making enquiries about you, then you have to weigh things up and he has decided what he wants to do."

O'Neill is in the market for a specialist right-back but has already stressed he would have no qualms about Mellberg continuing to play for the remainder of the season.

He has a great rapport with the Villa fans who gave him a standing ovation before and after Saturday's game with Blackburn when there was the possibility he might move to Juventus this month.

Mellberg said: "I am very happy with the agreement. It will be an important experience, at a prestigious club and in one of the most important leagues in the world.

"But now I want to try to finish on a high with Aston Villa and help them qualify for Europe. The club are making big strides and that would be a good way to finish."

Another defender could also be making a more immediate departure from Villa Park, with Bolton having agreed a fee for Gary Cahill.

The fee is understood to be between £4.5million and £5million, and has been accepted after Villa boss O'Neill rejected previous bids from Bolton and Birmingham.

It now appears Cahill, 22, who has just returned from a three-month loan spell at Sheffield United, will be heading to the Reebok Stadium.