Veteran lightweight Brian Cobb has been forced to withdraw from his WSOF 17 fight against Jonathan Nunez after injuring his knee on the treadmill the day before Saturday's event, World Series of Fighting Vice President Ali Abdel-Aziz told MMAFighting.com's Ariel Helwani.

Cobb (20-8) was expected to meet Nunez (5-0) in the night's co-main event, which airs live on NBC Sports Network as with the rest of WSOF 17's main card.

WSOF officials are currently looking for a replacement to fill Cobb's place and are hopeful to find one, according to Abdel-Aziz.

An undefeated 29-year-old fighting out of Syndicate MMA, Nunez earned a split decision over Ozzy Dugulubgov in his WSOF debut last March.

WSOF 17 takes place Jan. 17, 2015 at the Planet Hollywood Resort & Casino in Las Vegas, NV. Top welterweight contenders Jake Shields and Brian Foster collide in the night's main event.

An updated WSOF 17 fight card can be seen below.

Main Card (NBC Sports Network, 9 p.m. ET)

Brian Foster vs. Jake Shields

Johnny Nunez vs. TBD

Brendan Kornberger vs. Krasimir Mladenov

Bryson Hansen vs. Rudy Morales

Adam Cella vs. Danny Davis Jr.

Preliminary Card (Online, 7 p.m. ET)

Gil Guardado vs. Sinjen Smith

Joe Condon vs. Jimmy Spicuzza

Soslan Abanokov vs. Jordan Rinaldi

Donavon Frelow vs. Taylor McCorriston

Jamie Point vs. Trey Williams