Manchester City manager Pep Guardiola is unsure over the extent of defender Vincent Kompany's most recent injury.
The Belgium international walked off late in his team's 2-1 win over Swansea City in the EFL Cup on Wednesday.
Kompany, 30, was making his first appearance of the season, but he has seemingly suffered yet another injury setback.
Guardiola was unclear over the extent of the problem for the centre-back.
"The doctors are speaking with him and seeing what's up," he said, via the club's website.
"Hopefully it will not be a big problem, We're going to wait for the results from the doctors and I still don't have that or the opinion of my staff."
Second-half goals from Gael Clichy and Aleix Garcia put the visitors in control at the Liberty Stadium before Gylfi Sigurdsson's late goal.
Guardiola was pleased with what he saw from Kompany before the Belgian came off.
"It was good. It's not easy after a long, long time without playing, defensively he was so strong and he played really good," he said.
"After they scored the goal, I asked: 'What happened?' They said that Vincent had gone to the locker room, but hopefully it will not be a big problem. We will have to wait.
"If he's injured, he's injured, he cannot stay on the pitch. As I say, I don't know what happened. The doctor is testing, looking at what's going on and after we'll see."