Napoli start Lorenzo Insigne and Arkadiusz Milik, while Cengiz Under and Davide Santon play for Roma, but Alessandro Florenzi isn’t risked.
It kicks off at the Stadio San Paolo at 19.30 GMT.
Simone Verdi, Adam Ounas, Sebastiano Luperto, Amin Younes and Vlad Chiriches are unavailable, but Faouzi Ghoulam is back in the squad for the first time since he ruptured his ACL in November 2017.
While Ancelotti has been using the so-called ‘three-and-a-half-man defence’ system in the Champions League against Liverpool and Paris Saint-Germain, he returns to a more traditional 4-4-2 this evening.
That means Nikola Maksimovic and Piotr Zielinski on the bench, with Elseid Hysaj and Fabian Ruiz starting.
Arkadiusz Milik is chosen to play in attack rather than Dries Mertens, with Lorenzo Insigne having shaken off a knock to his ribs at the Parc des Princes.
Marko Rog isn't even on the bench due to a bruised foot.
Roma are missing injured Javier Pastore, Justin Kluivert, Diego Perotti and Rick Karsdorp, but Daniele De Rossi and Aleksandar Kolarov are fit to start after injury.
Alessandro Florenzi was reportedly going to play as part of the trident in a more advanced attacking role in place of Cengiz Under.
However, he is not risked after an injury concern, so Under starts with Davide Santon at right-back.
Juan Jesus is a surprise start in the centre rather than Federico Fazio.
Lorenzo Pellegrini maintains his position in the trequartista role behind centre-forward Edin Dzeko.
There has been an average of 2.9 goals scored per game in their last 34 meetings between Napoli and Roma. The only goalless game during this stretch was in 2015 at the San Paolo.
Napoli: Ospina; Hysaj, Albiol, Koulibaly, Mario Rui; Callejon, Allan, Hamsik, Fabian; Insigne, Milik
Napoli bench: Karnezis, Daniele, Malcuit, Maksimovic, Ghoulam, Diawara, Zielinski, Mertens
Roma: Olsen; Santon, Manolas, Juan Jesus, Kolarov; De Rossi, Nzonzi; Under, Lorenzo Pellegrini, El Shaarawy, Dzeko
Watch Serie A live in the UK on Premier Sports for just £9.99 per month including live LaLiga, Eredivisie, Scottish Cup Football and more. Visit: https://subscribe.premiersports.tv/