The card takes place April 27 from Newark, New Jersey.
McMann (6-0) won a silver medal in wrestling during the 2004 Summer Olympics. She was recently announced as the latest addition to the UFC’s female roster.
Gaff (10-4-1) appears set to become another member of that active roster. She will carry a three-fight win streak into the bout.
McMann should be the clear favorite in this one, as she appears to be a threat to Ronda Rousey’s position atop the bantamweight division.