Spanish tennis star Rafael Nadal is in the “final stages” of recovery from a knee injury and is on course to return to the ATP Tour next month, the head of the Spanish Tennis Federation’s medical team, Angel Ruiz-Cotorro, says.

Under the supervision of Ruiz-Cotorro, the world No.4 has had an ultrasound to determine the extent of his recovery from the knee ailment, which has kept him out of competition for six months.

The former world No.1 and 11-time Grand Slam champion had planned to return to action at an Australian Open tune-up in Abu Dhabi, but a stomach virus forced him to withdraw both from that exhibition tournament and the first Grand Slam event of the 2013 season.

Nadal is now scheduled to return at the Brazil Open, a clay-court tournament in Sao Paulo that starts on February 11.

“The tests confirm that Rafa’s recovery is proceeding favourably,” Ruiz-Cotorro said.

“Medically speaking, we are in the final stages and the results were very satisfactory and the return to the circuit is expected to proceed according to plan.”

Nadal said in August he was suffering from a knee ailment known as Hoffa’s syndrome, which is also known as fat pad impingement and involves pain and swelling around the bottom and under the kneecap.

The Spaniard began last summer on a high note by capturing a record seventh French Open title with a victory over world No.1 Novak Djokovic of Serbia in the final.

But he suffered a shock second-round exit at Wimbledon a couple of weeks later at the hands of unheralded Czech Lukas Rosol, considered one of the biggest upsets in the history of that prestigious tournament, and has not competed since.

Nadal, known for his physically demanding style of play and outstanding defensive skills, has struggled to stay healthy during his career, having been forced to withdraw from each of the four Grand Slam events due to various injuries.