UFC 219 has lost one of its biggest fights.

John Lineker, who recently replaced former bantamweight champion Dominick Cruz against Jimmie Rivera at the Dec. 30 pay-per-view event in Las Vegas, is out of the card due to a tooth infection, multiple sources confirmed with MMA Fighting’s Ariel Helwani on Sunday.

Lineker will have to undergo emergency surgery, sources told MMA Fighting. He should be cleared to return to training in three weeks.

The UFC is currently working on finding a replacement opponent for Rivera. There was no word as of Sunday afternoon on whether he’ll remain on the card.

Lineker (30-8), who accepted the fight on several weeks’ notice, most recently defeated Marlon Vera via unanimous decision at UFC São Paulo in October. “Hands of Stone” offered to be a Plan B in case something happened to either Cruz or Rivera at UFC 219, and he accepted the fight when Cruz fractured his arm in training.

Rivera (21-1) is now left without an opponent just days away from the promotion’s last event of the year. “El Terror” only fought once in 2017, defeating Thomas Almeida via decision back in July.

UFC 219 will take place at Las Vegas’ T-Mobile Arena and is headlined by Cris Cyborg vs. Holly Holm for the women’s featherweight championship.