When the UFC on FX 8 bout order was finalized, middleweights C.B. Dollaway and Cezar Ferreira were scheduled to fight on the night's main card. Dollaway dropped out and was replaced by Chris Camozzi. Now Ferreira is out and will be replaced by fellow Brazilian Rafael Natal.
Cezar Ferreira injured, Rafael Natal in against Chris Camozzi at UFC on FX on May 18— Guilherme Cruz (@guicruzzz) April 6, 2013
Cezar Ferreira tweets the reason he won't fight Camozzi: had to undergo a knee surgery yesterday. UFC told him he'll fight @ Rio on August 3— Guilherme Cruz (@guicruzzz) April 6, 2013
Mutante won TUF Brazil over Sergio Moraes at UFC 147, but this injury will make it over a year between fights.
Natal (15-4-1) submitted Sean Spencer at UFC on Fox 6 in January, and his biggest win (outside of the UFC) was a KO victory over Travis Lutter, whose Michael Jordan-esque dominance in Brazilian jiu-jitsu was no match for Natal's fists.
It is unknown whether or not Camozzi/Natal will stay on the main card, but given Camozzi's win streak and main card slot at UFC 154, I'd imagine this will be on the FX broadcast.