Manuel Pellegrini remains unsure over the extent of Fabian Delph's hamstring injury after the midfielder was forced off just 20 minutes into his Manchester City debut.
Delph performed a U-turn to sign for City from Aston Villa last week, but his first appearance - against Real Madrid on Friday - did not go to plan.
"Unfortunately, it looks like Fabian has a problem with his hamstring - we thought it would be useful for him to play 45 minutes but he got the injury so it's not the best news," Pellegrini said.
"We will have a more clear diagnosis from the doctor tomorrow."
City were swept aside 4-1 by Real, whose victory saw them clinch the International Champions Cup in Melbourne, climbing above Roma to top spot while City finished third.
"We knew before the game that it was difficult to play against a team with such good attackers without [Eliaquim] Mangala, [Vincent] Kompany and [Martin] Demichelis," Pellegrini said.
"You must also add the other players who are not here: [Wilfried] Bony, [Sergio] Aguero, Fernandinho and [Pablo] Zabaleta.
"Especially defending, we knew it would be a difficult game. Mangala was sick this morning so he could not play and Kompany is becoming a father again so is not here.
"I'm not concerned as we had a lot of missing players and then a lot of players have also arrived late so they've worked just five days.
"For them, they're just starting work - it's important in pre-season to work hard and it's good to play against important teams but you can't be worried about winning or losing at this point."
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