That’s the opinion of Greg Rusedski.
Nadal had to battle through his quarter-final against Karen Khachanov on Friday as he seemingly suffered from inflammation of the patellar tendon.
The 32-year-old has been troubled by patellar tendonitis for the majority of his career and struggled with a flare-up in the second set of 7-6 (7-2), 7-6 (7-2) triumph over Russian Khachanov in the Californian desert.
Nadal’s win set up a hotly-anticipated semi-final clash with long-time rival Roger Federer.
But the 17-time Grand Slam champion hinted that his 39th career clash with the Swiss icon may not go ahead due to his knee problem.
At his post-match press conference, Nadal insisted he would make a decision over whether or not to withdraw from the Indian Wells final four on Saturday morning.
And Rusedski insists Nadal should make the best decision for his long-term health – particularly with the clay-court season on the horizon.
The red dirt is Nadal’s favoured surface and he won four of five available titles on clay last year at Monte Carlo, Barcelona, Rome and Roland Garros.
He will hope to retain the French Open this year with a 12th triumph. That would see Nadal boast double the successes of the second-most successful player in the Paris tournament during the Open Era in Bjorn Borg.
And former world No 4 and Amazon Prime analyst Rusedski insists Nadal should make sure he is confident he can play.
He said: “It depends the recovery and what his team can do for him [whether he will face Federer].
“He’ll go in the cryochambers where he can get the recovery for the rest of the body.
“Then he’s got to figure out, ‘Do I take an injection and a painkiller overnight so I don’t feel anything?’
“But what will that have for long term damage for the major championships coming up?
“If he’s not fit, Roger is playing very, very well.
“Fingers crossed he can be at 90, 95 per-cent. A 90, 95 per-cent fit Nadal is still a very, very good player.
“[But] You could see from the look on his face [post-match, he’s absolutely gutted.”