Unbeaten heavyweight sensation Todd Duffee has suffered an undisclosed injury and has been forced to pull out of his fight against former UFC and Strikeforce title challenger Paul Buentello at UFC 107 on Dec. 12.

"[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.

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