The two men will meet in the UFC Mexico City feature bout Saturday night on ESPN+. Both have been training at altitude in Mexico for a month or more in order to get acclimated to Mexico City's 7,382-foot elevation.
Rodriguez (11-2), a native of Mexico, has not fought since one of the greatest knockouts in MMA history last November. In the fifth round of a fight he was losing, he landed an upward elbow as he was ducking away onto the head of an oncoming Chan Sung Jung. Jung hit the ground unconscious, and Rodriguez got the knockout with just one second remaining on the clock.
Rodriguez, 26, has won nine of his last 10 fights, and the UFC is hoping he can be a major draw in the Mexican market.
Stephens (28-16) has lost two straight fights and is coming off a close unanimous decision loss to Zabit Magomedsharipov at UFC 235 in March. Before the recent skid, the San Diego was resident was on a three-fight winning streak.
Stephens, 33, is ranked No. 9 among MMA featherweights by ESPN.
Grasso is ranked No. 9 at strawweight by ESPN; Esparza is No. 10.
Melo will be fined 30 percent of her purse, which will go to Aldana, per the UFC. Melo took the bout on just 10 days notice after Aldana's original opponent, Marion Reneau, withdrew.