
"[Withdrawing] was one of the hardest decisions I've had to make," the American Top Team fighter told Sherdog.com.
Making his debut for the UFC at UFC 102 in August, Duffee (6-0) scored the quickest knockout in the promotion's history by finishing Canadian Tim Hague in seven seconds.
Buentello (27-10) won his last two fights defeating Gary Goodridge and Kirill Sidelnikov on Affliction cards. Buentello, who went 3-1 for the UFC in 2005-2006, will likely still make his Octagon return on the card. Buentello relayed Mike Russow and Stefan Struve to Sherdog.com as possible replacements.