Former unified welterweight champion Keith Thurman was gearing up for his first fight since 2022, but it appears his return will be delayed.

Sports Illustrated's Chris Mannix reported that Thurman is expected to withdraw from his March 30 fight against Tim Tszyu due to injury. The PBC sought out a replacement opponent for Tszyu, and ESPN's Mike Coppinger reported that Sebastian Fundora will take Thurman's place and challenge Tszyu for his WBO junior middleweight title.

Boxing insider Dan Rafael reported earlier that Thurman sustained "some sort of injury" that put his fight with Tszyu "in doubt."

"How many times have you seen a fighter go to the doctor 12 days before a fight for an injury and the fight go through? It doesn't look good," a source told Rafael.

It was announced in January that Thurman and Tszyu would meet in the main event of PBC's first pay-per-view as part of its new deal with Amazon's Prime Video. Tszyu holds the WBO junior middleweight title, but the WBO declined to sanction the fight and it was set to take place at a catchweight of 155 pounds without the title on the line.

Thurman (30-1, 22 KOs) suffered the first loss of his career in July 2019 by a split decision against the legendary Manny Pacquiao. However, he's only fought once in the four-and-a-half years since that bout, defeating Mario Barrios by unanimous decision in February 2022.

Tszyu (24-0, 17 KOs) is coming off a stellar 2023 in which he claimed the WBO interim junior middleweight title in March by defeating former titleholder Tony Harrison by ninth-round TKO and following that up with a first-round knockout of Carlos Ocampo in June and a unanimous decision win over Brian Mendoza October. He was elevated to champion when undisputed champion Jermell Charlo was stripped of his WBO title.

Fundora (20-1, 13 KOs) last fought in April in a losing effort to Mendoza, which cost him his WBC interim junior middleweight title.