Antonio Conte is reportedly undecided on which system Napoli should use against Milan as he welcomes back David Neres in attack.
It kicks off at 20:45 CET (18:45 GMT) at the Stadio Diego Maradona in Naples.
The Brazilian is set to return from injury but should only come on in the second-half, meaning Conte could initially stick with the 3-5-2 formation that he had recently switched to because of his absence, according to Sky Sport Italia.
Giacomo Raspadori is expected to partner with Romelu Lukaku in attack, while Matteo Politano will operate as a right wing-back.