Torn ligaments in his foot/ankle most likely. He took a misstep, and his ankle twisted under him with a lot of his bodyweight on it. Thought it was minor, and kept doing things on it, and it swelled up and got worse. He says he doesn't have enough side to side stability to do the ESM, but is going to tape it up, and go for the pressing record.
Some are wondering if he is scared of Thor, and using this to get out of the comp.