The world title opponent of England's Dalton Smith - WBC super-lightweight champion Subriel Matias - has failed a drugs test.
Puerta Rican Matias was scheduled to fight against Sheffield's Dalton on January 10 in Brooklyn, New York.
It was revealed on Friday that Matias (23-2, 22 KOs) tested positive for a banned substance in a Voluntary Anti-Doping Association test.
"The WBC has received notification from VADA about an adverse finding from a test performed by WBC super-lightweight champion Subriel Matias," WBC president Mauricio Sulaiman said.
"The WBC has begun the investigation process as per the Clean Boxing Program protocol. I have spoken to our champion Subriel and his Promoter Mr Orengo, and they have expressed their absolute availability and cooperation as the process unfolds.
"The WBC will not make any further comments at this time."
SportNews News has contacted Matias' co-promoter Dmitriy Salita and VADA for comment
Matias now has until Monday December 1 to request a test of his B-sample. The 33-year-old won his title for a second time in July by defeating Dominican Alberto Puello.