The UFC champ will face Sara McMann on February 22, headlining UFC 170 at Mandalay Bay in Las Vegas.
Tate managed to take the undefeated Rousey into the third round -- longer than Rousey's previous seven fights combined -- but was taken out by an armbar.
UFC president Dana White made the surprise announcement at the post-fight press conference Saturday, but Rousey said she'll be ready.
“Dana actually approached me about this before this fight,” Rousey said. “I’m ready to get back into it. I’m still hungry.”
White said he hopes UFC women's bantamweight No. 1 contender, Cat Zingano, will be recovered from her knee injuries in time to face the victor of the Rousey-McCann bout.
“Cat Zingano goes back into training in March,” he said. “Hopefully she can stay healthy and we can do that fight."