United States midfielder Landon Donovan believes a long season is catching up with a "worn out" Manchester United star Wayne Rooney ahead of the World Cup finals in South Africa. Rooney has been troubled by an ankle and groin injuries in recent weeks, the latter of which forced him off early in the Reds' final Barclays Premier League encounter with Stoke last weekend. That match was Rooney's 49th for club and country in a season when the 24-year-old has shouldered United's hopes like no other time during his Old Trafford career. Donovan, who will lead the United States against England in their World Cup opener in Rustenburg on June 12 said: "Rooney is a top player. In my opinion, he is one of the best players in the world right now. "But the other part of it is that he has played a lot of games and he is tired. He is probably worn out. "Injuries are a part of that. Things happen when players are tired. When they just keep adding games to the schedule, it makes it difficult." He added on Yahoo! Sports: "Any time you come into a World Cup, because of the timing of it, big players who play a lot of games in Europe are coming right at the end of their season, so it is always an interesting dynamic how to balance that." Do you think the long season has taken its toll on Rooney? Have your say.