Madrid - Rafael Nadal's personal doctor said Tuesday they will do "everything possible" to enable the 16-time Grand Slam champion to compete at next week's season-ending Tour Finals in London.
"We have done and are going to do everything possible for him to be (in London)," Angel Ruiz Cotorro told Cope radio station on Tuesday, while making no guarantee of the Spaniard's presence in the English capital.
World number one Nadal pulled out of last week's Paris Masters before his quarter-final with a knee injury, placing his participation in London in doubt.
Nadal, who has suffered from knee and wrist injuries throughout his career, decided to withdraw after having his right knee strapped during a third-round win over Pablo Cuevas.
"Yesterday (Thursday), the pain was very strong but it was not the right moment to stop," Nadal said in Paris on Friday.
"I had treatment last night to try and be able to play today... But unfortunately it was impossible for me to return to the court."
Ruiz Cotorro said Nadal arrived in France "in good condition but started to suffer a bit after the first or second match".
"He was worried and we did a series of tests, but there was nothing serious detected in his tendon. We're going to start a treatment that will allow him to continue muscular work... so that he can go to London as he wishes."
"You have to be optimistic but also realistic faced with this situation at the end of an extraordinary season. You have to be careful. Health takes priority," the doctor added.
Nadal has never won the eight-man Tour Finals -- finishing as runner-up in 2010 and 2013 while missing two of the past three tournaments through injury.