Saturday's UFC Fight Night co-main event between Jeremy Stephens and Drakkar Klose was canceled due to an injury to Klose, the promotion announced on the broadcast.
Klose suffered a cervical sprain of the neck and a concussion when Stephens shoved him at the ceremonial weigh-ins Friday, his team told ESPN's Ariel Helwani.
The lightweight fight was one of the most anticipated matchups on the card. It will be rebooked for a later date, the UFC confirmed to ESPN's Brett Okamoto.
Klose said on Twitter he immediately felt his hand "go numb and neck tighten up" after the weigh-in incident.
"I woke up early this morning with a migraine/headache (and) nausea, and the only thing that made me feel better was laying in the dark," Klose wrote.
Klose said he vomited after resting for a couple of hours, and the UFC's doctor sent him to the hospital.
Stephens was set to compete at 155 pounds for the first time since 2012 after spending eight years in the featherweight division. The 34-year-old is riding a five-fight winless streak and was last victorious in early 2018.
Klose was looking to bounce back from a knockout loss to Beneil Dariush in March 2020. The 33-year-old was riding a three-fight winning streak before that defeat and holds a 5-2 record in the UFC.
"I tried to do everything I could to stay in this fight, but these issues are out of my control," Klose added.
A heavyweight bout between Andrei Arlovski and Chase Sherman will serve as the new co-main event.
Saturday's card will be headlined by a pivotal middleweight clash pitting former champ Robert Whittaker against Kelvin Gastelum.