Ultimate Fighting Championship (UFC) will be forced to make some last-minute lineup changes to the UFC Vegas 66 fight card, scheduled for this Sat. night (Dec. 17, 2022) on ESPN+ at the promotion’s APEX facility in Las Vegas, Nevada.

That’s because middleweight veteran Deron Winn suffered a “freak accident” and tumbled down the stairs after fainting at the UFC Performance Institute just outside of “Sin City,” leading to the dissolution of his Julian Marquez “Prelims” pairing.

“Yesterday at the PI I fainted and had a freak accident,” Winn wrote on Instagram. “I fell down the stairs, hit my head and neck pretty hard, sustained a mild concussion. They rushed me to the hospital and ran a bunch of tests on me. The majority of tests came back normal so I’m thankful for that. Since I suffered the concussion the UFC and medical (staff) has decided to pull me from my fight this weekend. I am devastated. I put so much work in these past couple months. I hope to rebook soon. Sorry to my opponent and sorry to all who have invested into me this camp. I’m heartbroken.”

Winn, 33, is coming off a technical knockout loss to Phil Hawes at the UFC Austin event last June and has now dropped three of his last four. As for Marquez, 32, he was stopped by Gregory Rodrigues — also at UFC Austin — but has won seven of his last 10.

The promotion is unlikely to find a replacement with just two days until showtime and there won’t be another UFC card until Jan. 14 in Las Vegas, so it remains to be seen if matchmakers try to rebook them for the new year or send them on their separate ways.

For the revised UFC Vegas 66 fight card and lineup click here.