MMA Fighting first reported the bout. Its spot on the card is not known at this time.
Perez (12-3-0) has rotated wins and losses throughout his UFC run, with the latest being a unanimous decision loss to Wellington Turman at UFC Fight Night Sao Paulo. All three of Perez's professional losses have occurred in the UFC. Half of Perez's wins are by submission.
Vieira (7-0-0) has already picked up two wins under the UFC banner over Oskar Piechota and Saparbek Safarov. Six of Vieira's seven career wins have come by way of submission. Vieira has yet to reach the judges' scorecards.
No location or main event has been announced for the expected UFC card on Saturday, October 10. Fightful is providing live coverage of the event.