Photos: Chris Colbert vs. Tugstsogt Nyambayar news conference

Junior lightweight contender Chris Colbert will face late replacement Tugstsogt Nyambayar in a 12-round bout Saturday in Carson, Calif. (Showtime).

Colbert (15-0, 6 KOs) is a top-rated 130-pounder and one of the sport’s fastest rising stars. Nyambayar (12-1, 9 KOs), a 2012 Olympic silver medalist for his native Mongolia, is moving up from 126 pounds for the fight.

Also on the card, Michael Rivera (20-0, 13 KOs) of the Dominican Republic will take on fellow lightweight contender Jon Fernandez (21-1, 18 KOs) of Spain in a scheduled 12-round bout.

Here are images from the news conference. All photos by Esther Lin of Showtime.