Rafael Nadal has pulled out of next week's Wimbledon due to a knee injury. Nadal said: "Unfortunately this year I won't be able to play at Wimbledon." The Spaniard, who has been struggling with tendinitis in his knees since being knocked out of the French Open last month, tested his fitness in two exhibition matches this week but after losing both decided not to defend his Wimbledon title just three days before the start of the major. He will be the first man not to defend his All England Club crown since Croatia's Goran Ivanisevic skipped the grasscourt grand slam in 2002. The 23-year-old was unconvincing on Thursday when he took part in an exhibition match against Lleyton Hewitt. Nadal, bidding to recover from knee troubles, struggled with his movement during the game at London's Hurlingham Club, losing 6-4 6-3. The player's coach and uncle Toni Nadal said after the game: "He is having difficulties bending and it seems his treatments aren't enough." The world number one was forced to withdraw from Queen's Club last week with knee trouble and was diagnosed with tendinitis in both quadricep tendons and fluid on the kneecaps. However, Nadal's problems in his first match since losing to Robin Soderling in the fourth round of the French Open have put his place at SW19 in jeopardy.