Juventus midfielder Hernanes will be out of action for three weeks because of a thigh injury.
The Brazil international was forced off at half-time in Juve's 1-0 Serie A win over AC Milan on Saturday, which moved the defending Italian champions into sixth place, nine points behind leaders Inter.
And the former Lazio playmaker will not return until next month after the severity of the injury was confirmed by Juve.
A training report on Juve's official website read: "Missing out again was Hernanes, who underwent tests to ascertain the exact nature of the problem picked up during last weekend's meeting with Milan.
"These revealed a first-grade tear in the adductor longus muscle in the midfielder's right thigh. He is expected to be out of action for approximately three weeks."
As well as the Champions League game with Manchester City on Wednesday, an expected three-week absence will see Hernanes miss league games with Palermo, Lazio and Fiorentina.
Hernanes will not feature in Juve's final Champions League group game against Sevilla, but could return in the last game before the mid-season break, which is away to Carpi.