Manchester City midfielder Kevin de Bruyne will be assessed by the club doctor on Sunday after limping out of the 3-1 Premier League victory over Swansea with a hamstring injury.
The Belgian, 25, pulled up in the 81st minute at the Liberty Stadium and was replaced by Jesus Navas.
Manager Pep Guardiola said he did not know how bad the injury was.
“It looks like it was muscular, but I am not a doctor. It is a pity because he is an important player,” he added.
“That’s why we have to have a big squad as everyone will help us.”
City’s next game is a Champions League trip to Celtic on Wednesday (19:45 BST).
They maintained their perfect start under Guardiola as Sergio Aguero scored twice and Raheem Sterling added a third.
They are four points clear of nearest rivals Tottenham after six league games.
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