Kaka’s withdrawal from Brazil’s World Cup qualifiers later this month has raised more doubts over his commitment to playing for his country.

The AC Milan player missed last year’s Copa America at his own request, saying he needed a rest. He hasn’t played for Brazil yet this year and will now sit out this month’s World Cup qualifiers away to Paraguay and at home to Argentina after knee surgery.

Kaka underwent an arthroscopy operation on his left knee on May 23 and initially said he hoped to be ready for the games, two of the most difficult and important in Brazil’s qualifying campaign for 2010.

But on Wednesday, Brazil coach Dunga withdrew him from the squad after being told by Milan that Kaka could only start training on June 10, five days before the match in Asuncion against group leaders Paraguay.

Brazil doctor Jose Luis Runco said Kaka had suffered damage to the meniscus caused by overuse, leading to discomfort.

It was the timing of the operation, immediately after the end of the Italian season, which has been questioned by some critics. They argue that if the injury was serious, Kaka should have undergone surgery earlier and that if it wasn’t that serious, he could have waited until after the qualifying matches, when he would have had several weeks to get better.

The Brazilian Football Confederation (CBF) are also upset at AC Milan’s refusal to allow Kaka to play in the Olympic Games as an overage player. Sources at the CBF said recently that the general feeling is that Kaka would have been released by the club if he had made a fuss.

Brian Homewood, Rio

There’s speculation in Marca today that if AC Milan do complete a deal to sign Ronaldinho at the end of the season, they might be prepared to let Kaka move to Real Madrid.

That got me thinking about what the other knock-on effects might be, and especially about whether Barcelona would feel obliged to sign another big-name player as a replacement.

My own view is that this would be a good time for Barcelona to go down a different route. Ever since Joan Laporta took over as president they’ve pursued a relentless policy of buying in top names, from Ronaldinho to Deco, Samuel Eto’o and on to Thierry Henry.

For the first couple of seasons it worked very well, as the club regained their status as European heavyweights, won the league title and went on to claim the Champions League. Now, though, is surely the time to say enough is enough.

If Ronaldinho does go, the coach (whoever that might be) will still be able to call on Henry, Eto’o, Messi, Bojan and Giovani to fill the forward positions. And that’s the main difference between Barcelona now and Real Madrid when they were reaching the end of their ‘galactico’ era.

Real were so focused on their megastars that the squad as a whole had a threadbare look about it, which became increasingly obvious as time wore on. Barcelona have no such problems and if they manage to resist the temptation to throw money at another major forward it should just mean more space to grow for Bojan et al.

What do you reckon? Should Barcelona go out and sign a direct replacement — a Kaka, for example? Should they throw money at the Premier League to get a Torres or a Gerrard, Cesc Fabregas or even Cristiano Ronaldo (presumably untouchable, but you never know)? And while we’re at it, should Real Madrid pursue their interest in long-term target Kaka? Give us your ideas in the comments.

PHOTO: Kaka reacts during Milan’s Serie A game against AS Roma in Rome March 15, 2008. REUTERS/Chris Helgren