His doctor and he have announced that the issue has been resolved a long time ago. It is like 5 years since he had any results attributed to/blamed to his knees. Before you start explaining how clay is friendlier surface, remember that it is not only this year, and also remember that they have been doing these treatments for ages before that.Tendonitis. wear and tear etc. It cant just be fixed with rest or surgery. He has tried resting it pretty much most of his career at certain points, but it just keep coming back more frequently as he ages.
I know this feeling all too well, as I used to do a particular physical job, that after 6-7 years of doing the same grind, my knee joints were starting to ache. But after I left the job my knees were fine. I know that if I went back there tomorrow, though, that in a few weeks time, id start getting pains.
If he starts running like a rabbit (which we know that he will) during the clay court season Nadal is officially the biggest joke to ever set foot on any sports arena.