AC Milan defender Alessandro Nesta has sustained a knee problem and might go under the knife soon. The World-Cup winner suffered a tendon rupture in training ahead of the Rossoneri's 4-0 loss to Manchester United in the UEFA Champions League. The full extent of the injury is yet to be determined, although Nesta has already undergone medical tests. "I have a torn tendon. We will judge whether to operate or undergo a conservative course of therapy," the 33-year-old said. "This tear probably happened in two different games and for this reason I will stop and evaluate whether to have an operation or not. "Perhaps I will manage to play again before the end of the season if I have the operation."