Alexander Gustafsson didn’t think much of a knee issue suffered during training. However, when he woke up the next day, he knew something wasn’t right.

Gustafsson was forced out of a planned September meeting with UFC light heavyweight champion Jon Jones earlier this week. He was replaced by Daniel Cormier.

“I was sparring and I felt my knee pop twice, but it didn’t hurt,” said Gustafsson, in an interview with “It just felt strange. I finished training and came home, and then I woke up the next morning and I could barely walk on my right leg. Then I felt the knee right away.”

Gustafsson (16-2) is headed for surgery to repair the torn meniscus, and is looking at five-to-six weeks of recovery after that. He lost to Jones last year via decision and was granted a rematch after defeating Jimi Manuwa.

As for the upcoming Jones-Cormier contest, “The Mauler” is expecting the champion to retain his title.

“Both are great athletes and it’s going to be a tough fight for sure,” he said. “But Jones has his height and reach advantage over ‘DC,’ so I think that will be the key thing in this fight. I think Jones by decision.”