Pep Guardiola has confirmed David Silva will miss "a few weeks" after picking up a hamstring injury in Manchester City's defeat to Chelsea.
The Spaniard was replaced by Ilkay Gundogan in the 68th minute of the 2-0 defeat at Stamford Bridge after falling to the turf while clutching the back of his right leg.
He is one of a number of players who will miss the visit of Hoffenheim to the Etihad Stadium on Tuesday in the Champions League.
Asked about his injury list, Guardiola said: "David Silva is not able. Kevin De Bruyne (knee) is not able. Danilo is not able. Sergio Aguero is not ready.
"We have 15 players available, so I can't do it too much (rotating). We are in the next stage which is important but we have to try and win every game to finish first."
Guardiola confirmed Silva is now a doubt for the busy Christmas period but Aguero may return from a muscle injury in time to face Everton on Saturday, live on Sky Sports.
"Sergio maybe has a chance for the weekend," Guardiola said.
Silva's injury may open the door for 18-year-old Phil Foden, who signed a new five-and-a-half-year contract with City on Monday, to make a rare Champions League appearance against Hoffenheim.
Guardiola is delighted Foden elected to stay and fight for place at the Etihad Stadium, rather than following in the footsteps of Jadon Sancho, who left to play regular first-team football with Borussia Dortmund.
The City boss also appeared to hint 19-year-old Brahim Diaz, who is out of contract at the end of the season and has been linked with Real Madrid, could be on his way out of the club.
"I am delighted and happy for Phil Foden," Guardiola said. "It would have been our desire for Jadon and Brahim to stay here but with Phil we convinced him.
"Keep going, and [for the] next six years he will be with us. He is a fighter and a City fan. [It is] a perfect deal."