Vidal has missed the last two games for Antonio Conte's side through injury, but it's reported that the midfielder will only return to the starting XI should he be 100% fit.
If Vidal doesn't return, Christian Eriksen could make a rare start for Inter, or Roberto Gagliardini could come into the side.
Achraf Hakimi came off the bench against Napoli in mid-week, and could be handed another start at right wing-back.
Defender Stefan De Vrij could be rested for the last game of the year, and so Andrea Ranocchia could replace the Dutchman.
Ashley Young is expected to drop to the bench for the game against Spezia, with Croatian Ivan Perisic thought to be coming in as his replacement.
Perisic, again linked with another departure from Inter in January, could be given one last opportunity to impress Conte.
Stefano Sensi could be in with a chance of being handed a starting berth. Sensi is highly rated by Conte, but the former Sassuolo midfielder has been hampered with a succession of injuries since joining Inter in 2019.
Nicolo Barella is expected to retain his starting position in central midfield, despite picking up a knock against Napoli on Wednesday.
Alessandro Bastoni is also expected to retain his place on the left-side of the defensive three for Inter.