The defender asked to be substituted with 10 minutes remaining and was replaced by the returning Nathan Ake.
However, the nature and severity of the issue aren’t yet known, with Guardiola yet to speak to his medical staff.
“He had some problems in the first half and in the second and he could not continue,” Guardiola said.
“We will see how he is. I didn’t speak to the doctors.”
The 1-1 draw with Villa means City’s unbeaten start to the season continues.
We remain second in the table, level on points with Tottenham, who visit the Etihad next Saturday, and a point behind Arsenal, who play their game in hand against Manchester United tomorrow.
And on Tuesday, our UEFA Champions League Group G campaign gets under way as we face Sevilla at the Ramon Sanchez Pizjuan.
Guardiola says, overall, he is pleased with the start we have made and insists there will be plenty of twists and turns to come.
“I am a positive person in general,” he said. “We have dropped four points so far and now we have the Champions League.
“Every game away is difficult in the Premier League - Newcastle, today - I know how difficult it is and the opponents are really good.
“The titles we won in the past were difficult and this will be no exception.
“The people talk, but I know this is just the beginning. A lot of things are going to happen this season.”
