According to information posted by the WBO, the four-belt world junior middleweight championship belt between Jermell Charlo and Brian Castaño, scheduled for Saturday, March 19th in Los Angeles, has been postponed. The letter states that Castaño has suffered an injury and the promoters want to reschedule the world unification rematch for May or June, but the WBO does not seem agreeable to the delay. Charlo holds the IBF, WBA and WBC championships, while Castano is recognized by the WBO. The two tried to unify the four belts last year, but the result was a well-received draw with each man retaining his respective belts.

An immediate rematch was booked for March, but with the news of Castaño's injury, but the WBO is now threatening to strip Castaño unless his next fight is a mandatory defense against Australia's Tim Tszyu prior to the unification rematch with Charlo. If the WBO adheres to this position, Castaño and Charlo may elect to go ahead with their rematch albeit with Charlo's three belts at stake. [If that happens, Boxingtalk will recognize the winner as the true world junior middleweight champion]. 

Tszyu was scheduled to face Terrell Gausha on the Charlo-Castaño II undercard. However, the WBO's decision is not final because the WBO has given Castaño and his promoter 24 hours to show cause why the mandatory should not be enforced before the unification rematch. The WBO's order included a letter from Tszyu’s promoter that said, “we have been very patient with the current champion Brian Castaño… But considering the information above, we requested the championship committee enforce the mandate for Tim’s out to fight for the world title."