Sergio Moraes told MMA Fighting's Guilherme Cruz that he has suffered a torn meniscus in his left knee, knocking him out of the TUF 18 Finale on Nov. 30 in Las Vegas.
MMA Junkie was the first to report Moraes' withdrawal from the event.
Moraes, who found about the extent of his injury this week, will need surgery for the injury. He was expected to face Sean Spencer in a welterweight fight at the event.
There is no timetable for his return. Spencer doesn't have a new opponent as of yet.