Former world number one Rafael Nadal admits it could be months before he is back to his best following the injury that wiped out the second half of his 2012 season.
The 26-year-old has fallen to fourth in the ATP rankings and has not played since his shock second-round exit at Wimbledon in June.
He will return to action for the first time since suffering a partial tear of the patella tendon when he lines up alongside Andy Murray and world number one Novak Djokovic at the Mubadala Tennis Championship in Abu Dhabi later this month, just a few weeks after returning to the practice court.
But while the player says his recover from injury is on track, he admits it may not be until well into 2013 that he returns to his best.
"I don't expect to return and win the Australian Open," he told Spanish radio.
"I have to be realistic. The results will not worry me in the first tournaments back.
"I have to take into account my form after so long out. It wouldn't bother me if I slipped down to 15th in the world as long as inside I knew was able to continue.
"I want to be 100 per cent in time for Monte Carlo and the run-up to Roland Garros."
Nadal, who won a record seventh French Open title in May, revealed he could have gone under the knife to recover from his injury, but was advised against it.
"I have to look at my career with a five-year view," he said.
"I considered having surgery, but the doctors have always preferred not to take risks with my treatment."
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