Constantin Ursu’s first defense of his Commonwealth welterweight title against Ryan Amos has been postponed due to a biceps injury, according to a social media post by Amos’ manager, Scott Calow.

Ursu-Amos was supposed to headline on May 25 at York Hall in London, main-eventing a show streaming on DAZN. The Top Tier Boxing promotion will still go forward on that same day and venue, but with a new main event: a super middleweight bout between James Osborne, 8-1 (1 KO), and Liam Forrest, 3-0-1 (0 KOs).

Ursu, 13-0 (6 KOs), won the vacant Commonwealth belt in March with a seventh-round knockout victory over the 13-1 Eithan James.

Amos, 15-2-2 (2 KOs), has won two straight against gimme opponents since losing on points to the 8-1 Bilal Fawaz last October.

“Amos will have a fight on July 5 to keep busy on a show which will also include another five of our boxers,” Calow posted on social media.

David Greisman, who has covered boxing since 2004, is on Twitter @FightingWords2. David’s book, “Fighting Words: The Heart and Heartbreak of Boxing,” is available on Amazon.