What's the matter with Jo Tsonga atm ?

I mean, i wanna know what his health problems are...he happens to be the only guy who was able to properly humiliate the new tennis king in 2008, no ?

I guess that's a thread moved from GM to Jo's forum?
All the informations are in the "Get well soon" thread:
http://www.menstennisforums.com/showthread.php?t=124298
He had surgery on his knee at the end of May, has been in rehab during all that time and resumed the training not even 2 weeks ago.
He should be back for the USO, though.