A planned light heavyweight bout between Stephan Bonnar and Matt Hamill scheduled for UFC Fight Night 13 is now off due to a knee injury sustained by Bonnar during training, according to Kevin Iole of Yahoo!

The card, which is scheduled for April 2 in Broomfield, Colorado, will be headlined by Kenny Florian vs. Joe Lauzon and Karo Parisyan vs. Thiago Alves.

A replacement for Bonnar has yet to be named.

Iole is reporting that Bonnar sustained the injury last Tuesday and could be sidelined up to six months as a result of torn ligaments in the damaged left knee.

Bonnar last fought at UFC 77 on October 20, 2007 when he defeated Eric Schafer by submission.