UFC 240 has lost a preliminary bout with less than 48 hours to go until fight time because of a failed drug test.
The substance for which Lemos tested positive has yet to be publicly identified.
Both fighters were slated to make their Octagon debuts at UFC 240.
UFC 240 is expected to move forward with 11 bouts, pending the outcome of Friday’s weigh-in, with featherweight champion Max Holloway putting his belt on the line against former lightweight titleholder Frankie Edgar. Cris Cyborg enters the final fight of her UFC contract by facing Felicia Spencer in the UFC 240 co-main event in Edmonton, Alberta, Canada.