His patella popped out of the groove in his femur. He didn't sprain his MCL, or tear his PCL or ACL and decide to play on it. For all we know, he has a pretty flat patella or shallow groove and it's prone to slipping over anyway with very little negative effects on anything else, it just never showed up until now. If it didn't break anything on the back of the patella or chip a condyle structurally, there is likely nothing more to worry about.
Unless of course they think he got lucky avoiding any of that damage in the first place. In which case he won't be playing this week or next because 1 or 2 weeks won't be enough time for it to heal enough to realistically avoid it happening again from being the patellar tendon being stretched.
Anyway, the integrity of his knee was not compromised like RGIII's was at all. It's not even close to a similar situation. I went and got some stuff off our boat yesterday before it goes in for storage and listened to Tiki and some other T named guy and Tiki was going off about his knee being dislocated and what a mistake it would be to play him and all I could think is, people are really misinterpreting what happened. Sure this injury can be bad, if other stuff happened with it sliding out, but it also could mean very little if nothing did and the anatomy is right.