Miguel Cotto has been stripped of his WBC middleweight title just four days before he was due to defend the belt against Saul 'Canelo' Alvarez.
Saturday's fight between Cotto and Alvarez in Las Vegas is one of the most eagerly anticipated of 2016, with a potential bout having failed to materialise in the past.
However, Cotto will not be recognised as the middleweight champion after the WBC claimed the Puerto Rican failed to comply with its rules and regulations.
The WBC confirmed that Alvarez will be the champion if he wins, though.
"The World Boxing Council worked tirelessly through a process that began over two years ago to secure the celebration of the highly anticipated fight between Miguel Cotto and Saul 'Canelo' Alvarez," a WBC statement read.
"The WBC is proud of that accomplishment that is giving boxing fans around the world a very important fight to see.
"After several weeks of communications, countless attempts and good faith time extensions trying to preserve the fight as a WBC World Championship, Miguel Cotto and his promotion did not agree to comply with the WBC Rules and Regulations, while Saul Alvarez has agreed to do so. Accordingly, the WBC must rule on the matter prior to the fight.
"The WBC hereby announces that effective immediately it has withdrawn recognition of Miguel Cotto as WBC World Middleweight Champion. If Saul 'Canelo' Alvarez wins the fight against Cotto, he will be recognised as the WBC middleweight world champion.
"The WBC's decision is premised on the fact that Miguel Cotto and his camp are not willing to abide by the governing WBC Rules & Regulations, and the specific conditions the WBC established to sanction the fight. Simply put: they are not willing to respect the very same rules and conditions which applied to Cotto becoming WBC champion.
"The WBC wishes Miguel Cotto the best of luck as we truly regret the course of action which led to them taking such decision."