I think last year it was something in the glutes/ high hamstring/ hip area. He actually was wearing compression under the singlet to help.From what I could see, it was his right knee.
He wasn't moving as well during the match and when he got of the mat, he had a slight limp to his walk.
Don't know how serious it is, but it reminded me a lot of his injury he had against Dean at the National Duals last year.