The UFC matchmaking team is working overtime this week, particularly focusing on the UFC on Fox 9 fight card slated for Dec. 14 in Sacramento, Calif.
UFC officials announced the bout on Wednesday.
Castillo (16-5) has the home field advantage, training alongside teammates Urijah Faber and Chad Mendes at Team Alpha Male in Sacramento.
He’ll hope to parlay that advantage into another victory, adding to his recent back-to-back successes. Castillo enters the fight having scored unanimous decision victories over Tim Means and Paul Sass in his last two outings.
Barboza has also won his last two fights, submitting Lucas Martins and TKOing Rafaello Oliveira.
A lightweight championship bout between Anthony Pettis and Josh Thomson headlines the event at Sleep Train Arena.