"I can say nothing about the injury. Seriously, I would would prefer not to talk about it," said the 24-year-old.
"For respect to the winner and a friend I'd prefer to talk about the match."
The defeat ended Nadal's hopes of holding all four Grand Slam titles at the same time - the so-called 'Rafa Slam'.
Ferrer goes on to play Britain's world number five Murray and Nadal believes that although his compatriot is the underdog, he can still emerge victorious.
"He's playing fantastic. But I think he's not the favourite," he added. "But if he keep playing like this, hopefully he can have a good chance to be in the final or win the tournament. I would love that.
"David is a fantastic person and is a close friend of mine so I wish him all the best.
"I think that Andy is playing very good, too, but David is playing at high level, no? If he's able to keeps playing like this, I think he is going have a good chance."
