The Bray lightweight was set to challenge champion Anahi Esther Sanchez tomorrow at the Principality Stadium, but the Argentinian has been stripped of the title following a failure to make weight.
Taylor came in at 134.5lbs, however the two-weight champion came in one pound over the 135lbs limit at the weigh-in this afternoon at the Motorpoint Arena and was given two hours to shed the excess.
Sanchez was either unable or chose not to do this, and remained over the limit when she retook to the scales in the last hour.
Therefore she has been stripped of the belt she won last month in a vacant title fight with countrywoman Cecelia Mena.
The fight on the Joshua-Takam Sky Box Office undercard tomorrow will still take place, with an agreement being reached between the two sides, but the vacant belt will now be on the line for Taylor alone.
Should Sanchez defeat Taylor, the belt will remain vacant.
Watch Katie Taylor v Anahi Sanchez weigh-in and head-to-head