Milan are forced to make changes with Giacomo Bonaventura and Lucas Biglia, while Napoli use Hirving Lozano with Lorenzo Insigne, but Suso pulled out in the warm-up.
It kicks off at San Siro at 17.00 GMT.
You can follow all the build-up and action as it happens from this game and Torino–Inter on the LIVEBLOG.
Milan are forced to make changes with Giacomo Bonaventura and Lucas Biglia, while Napoli use Hirving Lozano with Lorenzo Insigne, but Suso pulled out in the warm-up.
It kicks off at San Siro at 17.00 GMT.
You can follow all the build-up and action as it happens from this game and Torino-Inter on the LIVEBLOG.
The Rossoneri are struggling in the bottom half of the table, as although performances have slightly improved under Stefano Pioli, they have still lost three of their last four games.
Their biggest problem is scoring goals, finding the net only three times in four rounds.
Krzysztof Piatek retains his spot upfront, but Jack Bonaventura is picked ahead of Rafael Leao to replace the suspended Hakan Calhanoglu.
Suso was in the starting XI, but pulled out during the warm-up with a stomach problem, making way for Ante Rebic.
Ismael Bennacer also sits out a ban, so Lucas Biglia comes in, again freezing out Franck Kessie.
Andrea Conti gets a rare start at right-back and Mateo Musacchio returns from injury, but Samu Castillejo, Ricardo Rodriguez, Leo Duarte and Fabio Borini are out.
Napoli have been in a crisis of their own making, as on top of stuttering results that left them in seventh place, they’re also in-fighting to an unprecedented degree.
Just before the break for international duty, the squad rebelled against club orders to go into a training retreat.
They were booed off the pitch following the 0-0 draw with Genoa, are without a win in four rounds and President Aurelio De Laurentiis has promised huge fines to punish the mutineers.
The players and coach Carlo Ancelotti were also banned from speaking to the media.
Arkadiusz Milik, Mario Rui, Lorenzo Tonelli and Faouzi Ghoulam joined Kevin Malcuit on the treatment table.
Kostas Manolas is only on the bench after his rib injury, with Chucky Lozano and Lorenzo Insigne upfront.
It moves Piotr Zielinski to the left flank, dropping Dries Mertens to the bench.
Napoli have lost only one of their last 16 Serie A encounters with Milan, winning nine and drawing six.
That outlier was a 2-0 result in December 2014.
A home defeat would be historic, because Milan have never lost eight of their opening 13 Serie A games in a single season.
These are the two clubs who have performed worst compared to last term, as Napoli have 19 points (28 at this stage last season) and Milan 13 (21).
Milan: G Donnarumma; Conti, Musacchio, Romagnoli, Theo Hernandez; Paqueta, Biglia, Krunic; Rebic, Piatek, Bonaventura
Milan bench: Reina, A Donnarumma, Calabria, Leao, Caldara, Gabbia, Kessie, Brescianini, D Maldini
Napoli: Meret; Di Lorenzo, Maksimovic, Koulibaly, Hysaj; Callejon, Allan, Elmas, Zielinski; Lozano, Insigne
Napoli bench: Ospina, Karnezis, Fabian Ruiz, Llorente, Luperto, Mertens, Younes, Manolas, Gaetano
Ref: Orsato