Key Manchester City trio Vincent Kompany, Joe Hart and Yaya Toure are doubts to face Borussia Monchengladbach in the Champions League on Wednesday.
The setback for manager Manuel Pellegrini comes after his side were beaten 4-1 at Tottenham on Saturday -- their third defeat in four games.
A 2-1 home loss to Juventus in their Group D opener heightened the importance of winning on Wednesday, but they will be without a number of players in Germany.
David Silva, Eliaquim Mangala and Fabian Delph all missed the Tottenham game, as did Wilfried Bony, Gael Clichy and Kelechi Iheanacho.
Things got worse at White Hart Lane when Toure came off with a hamstring complaint, while an ongoing calf issue saw captain Kompany withdraw from the squad before kickoff.
Hart was on the bench due to a back twinge, adding to City's problems ahead of the trip to Monchengladbach.
"Joe had a problem with his back during the week," City boss Pellegrini said.
"He could train just one day this week, and that's why I decided to play [Willy] Caballero. Joe was not 100 percent.
"Yaya had some problem with his hamstring, and we don't know [if they will be fit]. We must wait for Sunday or Monday to decide if they are 100 percent.''
The prognosis on centre-back Kompany seems more clear-cut, with Pellegrini saying: "I don't think he will [be available on Wednesday]. At the beginning, he was fit to be on the bench.
"In the warm-up, he felt some problem in his calf. We will see in the way he develops in the next few days."
City struggled without Kompany, Toure and Hart as Kevin de Bruyne's first half goal was emphatically wiped out at White Hart Lane.
Eric Dier, Toby Alderweireld, Harry Kane and Erik Lamela netted as Pellegrini's men crashed to defeat, but the City boss dismissed suggestions that the side had lacked leaders.
"No -- I never complain about players that cannot play,'' he said.
"I think this team played very well in first 45 minutes and maybe deserved a better score.
"After that, two set pieces... and that's not about leaders. It is about marking, concentration. That decided the game."
He called on City to approach every game like a cup final after the defeat.