Pep Guardiola has described the suspected hamstring injury suffered by Kevin De Bruyne as "a pity" as Manchester City await a scan for the playmaker.
The Belgium international had to be replaced by Jesus Navas with just nine minutes remaining of City's 3-1 win at Swansea City on Saturday after going down to receive treatment.
De Bruyne will have a scan on Sunday to determine if his involvement for Wednesday's away Champions League game against Celtic and beyond will be affected.
"From the way he reacted, I think it's a muscular injury but I am not a doctor," Guardiola said after the match,
"I don't know how serious it is so we will travel back and then see what the doctor says.
"It's a pity as Kevin is an important player for us. That's why we have to have a big squad as everyone will help us."
City have won 10 consecutive matches to start Guardiola's reign in style, with De Bruyne playing in all but one of those games.