Heavyweight prospect Todd Duffee forced out of UFC 107 with undisclosed injury

Fast-rising heavyweight prospect Todd Duffee (5-0 MMA, 1-0 UFC) has been forced to withdraw from "UFC 107: Penn vs. Sanchez."

Sherdog.com was the first to report Duffee's decision, and MMAjunkie.com (www.mmajunkie.com) has since confirmed the report.

Duffee had been slated to face four-time UFC veteran Paul Buentello (27-10 MMA, 3-1 UFC) at the Dec. 12 event in Memphis, Tenn.

Duffee refused to reveal the nature of the injury that forced him out of the contest to Sherdog.com, and sources close to the fighter would only reveal to MMAjunkie.com that the 24-year-old was "very disappointed" to withdraw from the bout.

A timeframe for Duffee's return wasn't immediately known.

Duffee had hoped to build on the momentum of an impressive seven-second knockout of Tim Hague at UFC 102 in August.

A new opponent for Buentello has not been established, though Sherdog.com identified Mike Russow (12-1 MMA, 1-0 UFC) and Stefan Struve (18-3 MMA, 2-1 UFC) as possible options.

Buentello returns to the UFC after a six-fight run outside of the organization in which "The Headhunter" put together a 5-1 record. Buentello's most recent trip to the octagon was a February 2006 TKO of Gilbert Aldana. The win capped off a 3-1 UFC run for the Texan.

For the latest on "UFC 107: Penn vs. Sanchez," stay tuned to the UFC Rumors section of MMAjunkie.com.

(Pictured: Todd Duffee)

Check out more UFC News at MMAjunkie.com. This story originally appeared on MMAjunkie.com and is syndicated on Yahoo! Sports as part of a content-partnership deal between the two sites.