BARCELONA, Spain -- Rafael Nadal's doctor says the 14-time Grand Slam winner will receive stem cell treatment on his ailing back.
Angel Ruiz-Cotorro told The Associated Press by phone on Monday that, "we are going to put cells in a joint in his spine" next week in Barcelona.
The Spanish tennis star was already sidelined for the rest of the season after having his appendix removed last week.
Ruiz-Cotorro, who has worked as a doctor for Nadal for the past 14 years, said Nadal's back pain is "typical of tennis" players and that the treatment is meant to help repair his cartilage and is similar to stem cell treatment Nadal received on his knee last year.
He said Nadal is expected to return to training in early December.
Nadal experienced severe back pain during the final of the Australian Open in January when he lost to Stan Wawrinka.
"(Nadal) has a problem typical in tennis with a back joint, he had it at the Australian Open, and we have decided to treat it with stem cells," Ruiz-Cotorro said.
He said that stem cells were recently extracted from Nadal for a cultivation process to "produce the necessary quantities."
"When we have them we will put them in the point of pain," he said, with the goal of "regenerating cartilage, in the midterm, and producing an anti-inflammatory effect."
Nadal, now 28, won a record ninth French Open along with three other titles this season before a stunning loss to teenager Borna Coric at the Swiss Indoors in October dropped him to No. 3 in the ATP rankings. That tournament was only his third since Wimbledon due to a wrist injury.
The Mallorca island native has struggled with injuries over recent years.
A knee injury caused him to miss several months in 2012 before coming back to full strength to win 10 titles in 2013, including the US Open and again dominating at Roland Garros.
Nadal's 14 Grand Slam titles ties him with Pete Sampras on the all-time list led by Roger Federer and his 17 victories.