The German suffered a knee injury in the 2-0 win over Watford on Wednesday and looks set for a lengthy spell on the sidelines.
Zabaleta confirmed Gundogan has damaged the same knee he dislocated earlier in the year, a setback that saw him out of action for four-and-a-half months and delayed his City debut until mid-September.
“Yeah, it looks bad,” Zabaleta said. “It’s the same knee [as the injury he suffered in May].
“Probably he will be assessed tomorrow, he’ll have a scan and see how bad it is.”
Good morning everyone. Gutted for @IlkayGuendogan I wish you a speedy recovery and I'm sure you will come back stronger 💪🏼💪🏼💪🏼— Pablo Zabaleta (@pablo_zabaleta) December 15, 2016
Having worked his way to full fitness and played his way into Pep Guardiola’s side, it’s a cruel blow for Gundogan - but Zabaleta says the whole squad are behind him.
“We feel so sorry for him because it’s been quite tough for him at the beginning of the season,” he said. “He has been working so hard and he was playing well.
“Unfortunately, now it is the same knee. But he has to keep strong and see how bad it is.”