UFC on Fox 23 is a mixed martial arts event that will be held by the Ultimate Fighting Championship with a Women's Bantamweight main event card between Valentina "The Bullet" Shevchenko (58-2-1, 21 KO's) fighting out of Lima, Peru and her opponent Julianna "The Venezuelan Vixen" Peña (8-2-0, 3 KO's) fighting out of Spokane, Washington. This is the preliminary card and it is airing live tonight from the Pepsi Center in Denver, Colorado.The 6 scheduled preliminary bouts are as follows:Bantamweight: Raphael Assunção vs. Aljamain SterlingLight Heavyweight: Luis Henrique da Silva vs. Jordan JohnsonLight Heavyweight: Marcos Rogério de Lima vs. Jeremy KimballMiddleweight: Nate Marquardt vs. Sam AlveyMiddleweight: Eric Spicely vs. Alessio Di ChiricoWelterweight: Bobby Nash vs. Li Jingliang