A knee injury suffered in training has forced Brian Ortega out of a planned main event with Chan Sung Jung at UFC Fight Night 165 in South Korea. No replacement to keep "The Korean Zombie" on the card set for December 21 has been announced.

Ortega revealed on social media that he suffered a torn ACL. He has not competed since losing to Max Holloway for the UFC featherweight title in 2018, suffering his first career defeat.

"Thankfully, it was only a partial tear so I'm already rehabbing it and the plan is to be back to 100 percent in 2-3 months," Ortega wrote. "I didn't want to let down the fans, the Zombie and the UFC, so I strongly considered pushing through it and fighting anyways but according to doctors, the risk of a full rupture in the fight was high and that would put me out for up to a year.

"Sorry guys, I gotta take care of this right now but I'll make it up to all of you (in) 2020, I promise."

Jung, a native of South Korea, has not competed in his home country since 2008 before he signed with the UFC. The card currently features Volkan Oezdemir vs. Aleksandar Rakic and several other South Korean fighters.