Rafael Nadal's uncle and coach, Toni Nadal told the DPA news agency that the ATP world number three is undergoing stem cell treatment in an attempt to alleviate the back problems that have plagued him all season.

"He's had them for the past six months", said Toni Nadal. "It's stem cell treatment, and doing it properly requires five weeks", he added when explaining why they did not take advantage of the three months between July and October. "Because we all thought that he'd play at the US Open, we were more focused on his wrist injury, which looked to be healing well".

Nadal picked up his back injury in January at the Australian Open and it went on to plague him for most of the year, said Toni Nadal. "It affected his mood somewhat", he explained with regards to Rafa's back freezing up midway through the final against Wawrinka. "I'm not saying it was completely down to his back, but it's true that he wasn't fit to compete to the best of his ability", he added.

According to his uncle, Nadal has had a "bitter-sweet" season. Aside from the back problems he picked up in January, he also suffered a wrist injury in July which sidelined him for three months. Then he had appendicitis. Nadal is using his time out after the surgery to undergo treatment on his back. "That's why he'll be back in training in December, because the treatment takes five weeks. Either way, he couldn't postpone surgery on his appendix".