City must pay £43m to bring Benfica's Luiz to Manchester

Manchester City will need to pay €50m (£43m) if they are to bring the Benfica defender David Luiz to Eastlands, a huge investment in a player who is as yet uncapped by Brazil and who will take a lot of persuading to give up the prospect of Champions League football next season.

Luiz's potential has led to a number of clubs, including Real Madrid, Barcelona, Juventus and Bayern Munich monitoring his progress, though the Benfica president, Luis Filipe Vieira, declared this week that only one of his title-winning squad – Oscar Cardozo – will be allowed to leave the Estadio da Luz for less than the value of their release clause. Luiz, 23, contracted until 2014, has a £43m release clause.

City manager Roberto Mancini's interest is understandable, given the widely held view that Luiz, who turned down the opportunity to join Real Madrid to play for their second team a year before arriving at Benfica in 2007, is the best defender Portugal has seen in 20 years. Real's interest may be revived if Jose Mourinho arrives at the Bernabeu this summer given that Luiz, like many of the Benfica side, shares an agent – Jorge Mendes – with Mourinho.

City certainly have the greater buying power now, though Luiz is deeply attached to Benfica and the club's fans – he is the one player who runs across to applaud the supporters after every game – and sources in Portugal believe Vieira may try to persuade the player to stay for one more year and leave next summer, possibly a Brazil international by then and hence more valuable. Benfica may not be in need of the money which the sale of Luiz brings in, if Cardozo and Angel di Maria, their brilliant left winger, both depart this summer. Real are considering Di Maria's £40m buy-out clause, and selling the two players may bring in a total of £50m for the newly-crowned Portuguese champions.

Talks between City and Benfica on Luiz are some way off, with Vieira, his manager Rui Costa and the player all currently in the United States for Benfica's end-of-season tour. Vieira, who handles transfer business at the Lisbon club, will then holiday in Timor. But City, who also anticipate a drawn-out pursuit of Aston Villa's James Milner, badly need a player of Luiz's versatility after the poor seasons defenders Kolo Touré and Wayne Bridge have just had. Though the Brazilian, signed from Vitoria in 2007, has played mostly at left-back for Benfica this season, his more natural position is in central defence where his fine technical ability gives him the ability to advance into attacking positions with the ball and distribute well. He is also known for his aerial ability at corners.

The Portuguese media have been astonished by Dunga's unwillingness to select Luiz for Brazil but his rate of development suggests that he has the potential to become one of the best central defenders in the world. Luiz would certainly offer a foil to Jerome Boateng, who is more of a stopper, if the German defender's expected £11m move from Hamburg is completed. But he would be equally useful to Mancini as a full-back, given that Boateng, Vincent Kompany and Joleon Lescott could meet City's requirements in central defence.

Martin Petrov, who is out of contract at City, is very likely to leave this summer though the future of Sylvinho, who is in the same position, is less clear.

Meanwhile, Gianluigi Buffon's agent has dismissed suggestions that the player might be leaving Juventus, with both City and Manchester United having been linked with the Italy goalkeeper. Silvano Martina said: "Considering the ongoing reports, I want to remind everyone that Buffon is under contract with Juve and that next season he will play at Juve. When he was asked hypothetically where he would want to play if he left Juve, he always said his first choice would be England, but there is nothing else."