Shannon Gugerty has been tapped to replace Guillard on the card.
Sherdog reported the lineup change late Tuesday.
“Melvin is off the card, and they went through three or four opponents and settled on Gugerty,â€ Fisher told Sherdog.com.
Gugerty (11-2) has won eight-straight fights including a first-round submission of Dale Hartt in his UFC debut at UFC Fight Night 14 in July.
Fisher (21-4) rebounded from a unanimous decision loss to Frank Edgar at UFC 78 in late-2007 with a unanimous decision victory over Jeremy Stephens at The Ultimate Fighter 7 Finale in June.
Anderson Silva will put his middleweight title on the line against Patrick Cote in the UFC 90 main event. The pay-per-view card is also slated to featured Diego Sanchez vs. Thiago Alves, Tyson Griffin vs. Sean Sherk, and Thales Leites vs. Goran Reljic.