AC Milan's central defender Alessandro Nesta underwent right knee surgery on Monday and is expected to be back in action next month. The club's forecast that 33-year-old Nesta would have recovered from the operation in around '30 days' is encouraging news after initial forecasts that the 2006 World Cup winner might miss the rest of the season. The diagnosis was also welcome coming less than 24 hours after David Beckham's tore Achilles tendon in AC Milan's 1-0 win against Chievo on Sunday evening. Beckham is in Finland for surgery on the injury which looks to have dashed his dream of making England's 2010 World Cup squad. AC Milan are ranked second in Serie A, one point behind champions Inter Milan. 