Mike Maignan pulled out during the warm-up of the match with Juventus, so Marco Sportiello had to take over in goal behind a decimated Milan defence.
It kicked off at the Allianz Juventus Stadium in Turin at 17.00 UK time (16.00 GMT).
Maignan had originally been named in the starting XI and took part in the warm-up in Turin, but went back into the locker room touching his thigh.
According to DAZN, Maignan was struggling with an adductor issue and it was decided to leave him on the bench instead, giving Sportiello the gloves at the last minute.
Maignan had also missed the 3-3 draw with Sassuolo on April 14 and this is his fourth different injury of the season.
Another Milan injury
It is a further problem for Stefano Pioli to deal with, as he already has a decimated defence going into this showdown for second place.
Davide Calabria, Theo Hernandez and Fikayo Tomori all sit out bans following the fiery Derby della Madonnina against Inter, while Pierre Kalulu, Mattia Caldara and Simon Kjaer are all injured.
Luka Jovic and Tommaso Pobega are also on the treatment table, leaving limited options, so Yunus Musah is reworked as a right-back.