The Norway international has been sidelined for almost two months with a severe sprain and was believed to have had a wafer-thin chance of coming back against Newcastle United, but he missed out again as the Gunners slumped to a 1-0 defeat on Saturday.
Mikel Arteta will no doubt be pressed for an update on Odegaard in his pre-game press conference, although the Spaniard is likely to keep his cards close to his chest, and he will definitely be missing Takehiro Tomiyasu (knee), Kieran Tierney (hamstring) and Riccardo Calafiori (knee) in midweek.
With Odegaard absent at St James' Park, Arteta placed his faith in Kai Havertz, Bukayo Saka, Gabriel Martinelli and Leandro Trossard up front, but all four struggled to impact proceedings.
The former three should all hold their places, but Trossard is certainly at risk of the axe as Arteta rejigs his midfield, potentially moving Thomas Partey back to his more familiar number six position if Ben White is fit to start at right-back.
Gooners crying out for Ethan Nwaneri to start should see their pleas fall on deaf ears, as Partey, Mikel Merino and Declan Rice should comprise an experienced engine room at San Siro, where Arteta may sacrifice creativity for physicality if Odegaard is not risked.
Gabriel Magalhaes did not enjoy his finest hour against Newcastle after recovering from a knee injury, but the Brazilian's place should not come under any threat whatsoever.
Arsenal possible starting lineup:
Raya; White, Saliba, Gabriel, Timber; Merino, Partey, Rice; Saka, Havertz, Martinelli