Steve Burton on the news last night called it a 'calf strain'. Maybe he mispoke?
Rob, unfortunately is a guy whose minutes will have to be managed for his entire career. Anyone who relies on his legs as much as he does is bound to have knee problems sooner or later. What's worrisome is that he's having them sooner.
Which is why I wasn't a fan of Ime playing him 30 mpg earlier in the season. He has backed of a bit recently but I just think Rob is a guy who's always going to be dealing with something - just because of how he plays.