Less than 24 hours after finding a huge replacement for the UFC 294 main event, the promotion has once again pulled off a marquee short-notice change for the co-feature bout.

Paulo Costa was originally scheduled to compete against Khamzat Chimaev in the co-feature of the pay-per-view event in Abu Dhabi, but will not be medically cleared to compete due to a staph infection. Chimaev will remain on the card, and will now face former welterweight champion Kamaru Usman who is stepping up on 10 days’ notice.

UFC CEO Dana White officially announced the new matchup Wednesday on social media.

Usman, 36, moves up to middleweight following back-to-back welterweight title fight losses to current champion Leon Edwards. Prior to the consecutive losses, Usman reigned longly over the 170-pound division and racked up five title defenses. He has not competed since UFC 286 in March.

Chimaev, 29, has not fought for even longer. His most recent win was vs. Kevin Holland at UFC 279 in September. Chimaev missed weight before the bout. After some discussion between his team and the UFC brass, Chimaev ultimately elected to move up to middleweight, where he already has two wins in the UFC.

Costa, who is in Abu Dhabi, also revealed in a since-deleted social media post that he will have to undergo a second elbow procedure, just weeks after he had an initial one for a right arm bursa.

The co-main event switch-up comes less than 24 hours after White announced the previously scheduled main event between Islam Makhachev and Charles Oliveira was off and that Alexander Volkanovski would replace Oliveira, who suffered a cut in training Monday.

With the change, the UFC 294 fight card includes:

Islam Makhachev vs. Alexander Volkanovski – for lightweight title
Kamaru Usman vs. Khamzat Chimaev
Magomed Ankalaev vs. Johnny Walker
Ikram Aliskerov vs. Nassourdine Imavov
Muin Gafurov vs. Said Nurmagomedov
Tim Elliott vs. Muhammad Mokaev
Trevor Peek vs. Mohammad Yahya
Javid Basharat vs. Victor Henry
Abu Azaitar vs. Sedriques Dumas
Mike Breeden vs. Anshul Jubli
Muhammad Naimov vs. Nathaniel Wood
Viktoriia Dudakova vs. Jinh Yu Frey
Shara Magomedov vs. Bruno Silva

For more on the card, visit MMA Junkie’s event hub for UFC 294.