Former world No.1 Rafael Nadal has returned to training at his Mallorca base after nearly five months on the sidelines with a knee injury. "Today was my first training session after so many weeks out," the Spaniard said on his Facebook page "I am making progress and I hope to continue to do so." Nadal last played at Wimbledon on June 28 when he lost to the unseeded Lukas Rosol of the Czech Republic in the second round. The 26-year-old was subsequently diagnosed as suffering with Hoffa syndrome, an inflammation of the fatty tissue situated behind the kneecap in his left knee, a problem that has sidelined him several times over the years. He was unable to defend his title at the London Olympics, missed out on the US Open and was also unavailable for last weekend's Davis Cup final which saw the Czech Republic unseat Spain as title-holders. Nadal's world ranking has fallen to fourth behind, Novak Djokovic, Roger Federer and Andy Murray, and compatriot David Ferrer is close to moving past him also. There was no word on when Nadal would return to competitive action, but he has said that his next target would be to get fully fit in time for the year's first Grand Slam event - the Australian Open in the second half of January.