Muhammad replaces Khamzat Chimaev, who had to pull out because of lingering effects from his COVID-19 diagnosis.
"[Matchmaker Sean Shelby] is literally in the other room right now working on a new fight for Leon Edwards," UFC President Dana White told Okamoto at the time.
Edwards reacted to Thursday's news:
Muhammad is the No. 13 challenger in UFC's 170-pound rankings, one spot ahead of Chimaev, so the card isn't impacted much by the switch. The Chicago native has an 18-3 career record, with eight wins in his last nine bouts.
The 32-year-old obviously doesn't have a whole lot of time to prepare, and his next fight will only be slightly more than a month on from his unanimous-decision victory over Dhiego Lima at UFC 258 last Saturday.
That can play to Muhammad's benefit, though, since his stock would soar if he can take Edwards down on relatively short notice.
Edwards, meanwhile, is looking to get a title shot at Kamaru Usman, who successfully defended the welterweight championship against Gilbert Burns in the UFC 258 main event. The Jamaican also owns an 18-3 career mark.
A win over Muhammad would be his ninth in a row. With Edwards as the No. 3 welterweight challenger, Usman would make for the next logical opponent.