The scheduled welterweight clash between Andrew Todhunter and Albert Tumenov at UFC 188 has been canceled after Todhunter was declared medically unable to compete.The Las Vegas-based promotion announced the cancellation on Thursday night. UFC 188 takes place at Mexico City Arena in Mexico City on Saturday night and is headlined by a heavyweight title tilt between Cain Velasquez and Fabricio Werdum According to a report from MMAFighting.com , Todhunter passed out while trying to make weight. Todhunter was a short-notice replacement for Hector Urbina , who withdrew from the matchup with Tumenov due to injury. Todhunter is 7-0 as a professional, with all seven victories via submission.After falling to Ildemar Alcantara in his promotional debut, Tumenov has reeled off three consecutive triumphs, including knockout wins over Anthony Lapsley and Matt Dwyer . Most recently, he outpointed Nicholas Musoke at UFC on Fox 14.