Brian Castano is officially on the clock.

In the wake of an untimely injury forcing a postponement of his March 19 rematch with Jermell Charlo, Argentina’s Castano (17-0-2, 12KOs) is now at the mercy of the WBO. The unbeaten junior middleweight titlist has been ordered by the Puerto Rico-based sanctioning body to show cause as to why he should not have to commit to an overdue mandatory title defense versus Australia’s Tim Tszyu.

The fallout comes just hours after a breaking news story from BoxingScene.com revealing that Castano suffered a slight biceps tear during training camp ahead of his planned WBA/WBC/IBF/WBO/Iineal junior middleweight championship rematch with Houston’s Charlo (34-1-1, 18KOs). The bout was due to take place at Crypto.com Arena in Los Angeles, with the undercard to include Tszyu (20-0, 15KOs) in a crossroads bout with 2012 U.S. Olympian and veteran trialhorse Terrel Gausha. It appears that Tszyu and promoter Matt Rose—head of No Limit Promotions—are not interested in yet another delay to an already owed title shot, which in turn has forced the WBO’s hand.

“Please be advised that the WBO World Championship Committee confirmed receipt of email correspondence by Mr. Matt Rose of “No Limit” Promotions and representative of Tim Tszyu indicating that TGB Promotions informed Mr. Rose that the Undisputed WBO, WBA, WBC & IBF Jr. Middleweight Championship Contest between Jermell Charlo and Brian Castano scheduled for Saturday, March 19, 2022, at the Crypto Arena, in Los Angeles, California had been canceled due to an injury suffered by Brian Castano,” Luis Batista-Salas, chairman of the WBO Championship Committee informed TGB, Charlo and Sebastian Contursi—Castano’s manager—in an official letter, a copy of which was obtained by BoxingScene.com. “[T]herefore, Castano is unavailable to participate as scheduled.

“Consequently, TGB Promotions informed Mr. Rose that the Charlo/Castano would be rescheduled for either the months of May or June of 2022. Considering the preceding circumstances and Mr. Rose’s objection that the WBO Mandatory title defense is further delayed, he requests that this Committee proceeds with the immediate enforcement of the WBO Mandatory title defense between Brian Castano and Tim Tszyu accordingly.”

The WBO previously agreed to delay its ordering of the mandatory junior middleweight title fight, with the understanding that Castano would proceed with an undisputed rematch with Charlo. The two fought to a split decision draw last July 17, with Charlo winning 117-111 on one card, Castano winning 114-113 on another and the third card (114-114) producing the stalemate in their entertaining Showtime headliner from AT&T Center in San Antonio.

Charlo was eager to move forward with the rematch as early as possible, though forced to wait for the first quarter of 2022. Hopes of staging the fight February 26 were pushed back to March 19, which further tested the patience of the four sanctioning bodies—all of whom have mandatory challengers in waiting.

Pushing the fight out to May or later has drawn concern from Tszyu, which compromises the WBO’s position in granting another exception.

For now, the onus is on Castano and TGB to convince the sanctioning body otherwise.  

“TGB Promotions has 24 hours upon issuance of this notice letter to “Show Cause” why the WBO World Championship Committee shall not order the enforcement of the Mandatory Title Defense between Brian Castano and Tim Tszyu, and order negotiations immediately between the parties,” noted Batista-Salas.

Castano claimed the WBO title in a twelve-round, unanimous decision win over Brazil’s Patrick Teixeira last February 13. His lone defense came in the aforementioned draw with Charlo last July.

Charlo has made two defenses of the WBC title he regained in a December 2019 eleventh-round knockout of Tony Harrison, avenging a controversial points loss exactly 52 weeks prior. Both title defenses came in unification bouts, stopping Jeison Rosario in the eighth round of their September 2020 lineal/WBC/WBA/IBF championship clash, followed by the draw with Castano.

If the WBO orders Castano-Tszyu, Charlo would be left to satisfy his mandatory title defense obligations. Bakhram Murtazaliev (19-0. 14KOs) has been the IBF number-one contender since November 2019, though since accepting stay-busy fights on Charlo’s last two undercards. Israil Madrimov (8-0, 6KOs) became the WBA mandatory following a controversial ninth-round stoppage of Michel Soro last December 17 in Tashkent, Uzbekistan.

Jake Donovan is a senior writer for BoxingScene.com. Twitter: @JakeNDaBox