The Spanish midfielder was withdrawn with 12 minutes remaining at the Etihad Stadium, having earlier gone down under a robust challenge from Angelo Ogbonna in the Hammers’ penalty area.
Guardiola says it is too early to know exactly how serious the problem might be, but admitted the early signs were not too severe.
“He told me that he felt something,” said the City boss. “But I don’t think it was a big issue.
“I will know tomorrow exactly. He played really well today and we will see in the next days.
“He told me he had more caution after what happened near the goal. We will see tomorrow with the doctors.”
It proved to be a routine win for City, who were playing for the first time since our 2-0 defeat to Tottenham Hotspur 16 days ago, after the weather put paid to our original fixture against David Moyes’ side.
The game came just five days after UEFA’s ruling on the Club’s participation in the Champions League, but Guardiola declared he and his players remain focused on trying to finish the season as strongly as possible.
“All we can do is on the pitch and do what we have done the last four years and focus on that until the end of the season.
“I trust 100% completely my club what they have done. They explained to me the reasons why.
“We are going to fight like we have fought every single game and day we are together until the end of the season.
“We are optimistic that at the end the truth will prevail and next season we will be in the Champions League.”
