George St. Pierre revealed Thursday he sustained a neck injury during his middleweight championship fight against Michael Bisping on Saturday.

St. Pierre, who won the middleweight title after a four-year layoff, said he was injured in the first round of the fight on an elbow to the back of the head from Bisping.

“It looked very insignificant when it happened,” St-Pierre said, per MMAJunkie. “It wasn’t the strength of the hit. It was more the precision of it. It’s not his fault. We’re not allowed to hit there, but it was just in the heat of the fight, and it’s normal.

“My neck was so inflamed, when I was on the floor, I had a hard time posturing up because it was hurting very bad. It felt like I couldn’t contract my head to posture up. After the fight when I cooled down, it was terrible. It was like my neck couldn’t move. Now it’s still sore, but it got a lot better. I got treatment on it, so I’ll be back 100 per cent.”

St. Pierre added that his contract states his next fight in the UFC must be against interim middleweight champion Robert Whittaker, but the 36-year-old would not commit to a timeline for the fight.

“We’ll see what I want to do and where my head is,” he said. “I have no intention of holding onto the belt and freezing the division. That’s not what I want to do. Robert Whittaker is in my contract. If I want to fight again, it has to be against Robert Whittaker at 185 (pounds). That’s in my contract. I cannot, for example, go fight (welterweight champ) Tyron Woodley or go fight another guy.”

St. Pierre, who held welterweight belt from 2007-2013, said he has not decided what his next move will be after fighting Whittaker.