Just a week-and-a-half before UFC 117, Thiago Silva has been forced to withdraw from his preliminary matchup with fellow light heavyweight Tim Boetsch at the August 7 event in Oakland, California with a back injury, MMA Weekly reports.

Silva (14-2) was slated to return to action after dropping a unanimous decision to former champ Rashad Evans in January for his second loss in three fights after beginning his career with 13-straight wins, including four UFC victories.

Boetsch (11-3) was released by the UFC after falling to 2-2 inside the Octagon with a unanimous decision loss to Jason Brilz at UFC 96, but has since won three-straight to earn another shot with the promotion.

A search is now underway to find a replacement to meet Boetsch on the UFC 117 prelims.

The UFC 117 fight card is headlined by middleweight champ Anderson Silva vs. Chael Sonnen, and also features welterweight contenders Thiago Alves vs. Jon Fitch and Matt Hughes vs. Ricardo Almeida.

For complete UFC 117 coverage, including UFC 117 results on Aug. 7, stay tuned to ufcnews.info.