Sergio Aguero did not take part in training with Manchester City on Monday ahead of their UEFA Champions League opener with Juventus.
The striker suffered a heavy blow to the knee in a challenge by Scott Dann and was substituted after 24 minutes of the Premier League leaders' 1-0 win at Crystal Palace on Saturday.
Aguero cast further doubt on the likelihood of him facing the Italian champions on Tuesday by failing to appear as Manuel Pellegrini put his squad through their paces on Monday.
Fernandinho, an ever-present for City this season in midfield, and Samir Nasri were also not involved.
There appeared to be better news for Pellegrini as David Silva and Raheem Sterling, who missed out against Palace due to respective ankle and hamstring problems, both took part in the session.
Holding midfielder Fernando has not featured so far this term due to a groin problem but was back with the squad.