Rafael Nadal was stepping up preparation for Wimbledon by training on Mallorca's best grass courts on Thursday, an apparently positive sign that he intends to play in London.

The Australian Open and French Open champion said after his Roland Garros triumph at the start of June that he would only appear at Wimbledon if he could compete without needing anaesthetic injections in a troublesome foot.

The 36-year-old said he was given a couple of injections before every match and announced he would undergo radio frequency injections in a bid to feature at the third grand slam of the year.

Nadal is halfway towards a potential sweep of the four majors, defying the foot trouble by producing results that few saw coming. Rod Laver in 1969 was the last man to win all four singles majors in a calendar year.

Spaniard Nadal was pictured by organisers of the Mallorca Championships on Thursday, during a practice session on one of the tournament's plush courts.

Nadal, who hails from the island, is reluctant to undergo major surgery to prolong his career.

Wimbledon starts on June 27, and it is a tournament that Nadal has won twice, in 2008 and 2010.

He leads the all-time list of men's grand slam singles title winners, with 22 to his name now, two more than Roger Federer and Novak Djokovic have managed.

That is still one fewer than Serena Williams has managed during her stellar career, and the 40-year-old American rolled in to London on Thursday for another tilt at Wimbledon.

Due to injury, Williams has not competed on the WTA Tour since last year's championships at the All England Club.

She has received a wildcard into Wimbledon, where she has been a champion seven times, most recently in 2016.

Williams posted a video on Instagram of her arriving in London with daughter Olympia.

She intends to compete in doubles at Eastbourne, partnering Ons Jabeur, in the week leading up to Wimbledon.