Lineker, who is ESPN's No. 5-ranked bantamweight, was forced to pull out because of a tooth infection and underwent surgery Wednesday, according to a report by MMAFighting.com.
The UFC announced that a lightweight bout between Dan Hooker and Marc Diakiese will move up to Saturday's main card, which takes place at T-Mobile Arena in Las Vegas and will be headlined by a women's featherweight title bout between Cris "Cyborg" Justino and Holly Holm.
A new opponent for Rivera was not announced.
Lineker is the second opponent to have to pull out against Rivera (21-1). Rivera, No. 6 in ESPN's rankings, originally was supposed to face former champion Dominick Cruz on the end-of-year card, but Cruz was forced to pull out with an arm injury last month.