Luka Jovic leads the decimated Milan attack against his old club, while Giacomo Bonaventura and Nico Gonzalez hope to inspire Fiorentina.
It kicks off at San Siro at 19.45 GMT.
This is a head-to-head for position, as the Viola are only three points behind the third-placed Rossoneri going into the weekend.
Olivier Giroud begins his two-match ban for insulting the referee in a 2-2 draw away to Lecce.
Rafael Leao, Noah Okafor, Simon Kjaer, Ismael Bennacer, Mattia Caldara, Pierre Kalulu, Marco Sportiello and Marco Pellegrino are all injured.
That means Jovic is the only striker available against his former teammates, with 15-year-old sensation Francesco Camarda on the bench.
Ruben Loftus-Cheek is nowhere near fully fit either.
Fiorentina have issues too, as Michael Kayode, Dodo and Gaetano Castrovilli are out of action, with Luca Ranieri suspended.
Bonaventura is also up against his old club, with Nico Gonzalez, Riccardo Sottil and Lucas Beltran, who has shaken off bruised ribs.
Milan: Maignan; Calabria, Thiaw, Tomori, Theo Hernandez; Musah, Reijnders, Pobega; Chukwueze, Jovic, Pulisic
Fiorentina: Terracciano; Parisi, Milenkovic, Martinez Quarta, Biraghi; Arthur, Duncan; Nico Gonzalez, Bonaventura, Sottil; Beltran
Player statistic
12' | Arthur Melo | |||
Theo Hernández | 45+2' | |||
45+1' | Fabiano Parisi |
Fikayo Tomori | 56' |