Erling Haaland was substituted at half-time in Manchester City's 6-1 win against Bournemouth on Saturday after twisting an ankle.
City manager Pep Guardiola said he withdrew the striker as a precaution, but it was too soon to tell if Haaland would be available for Tuesday's Champions League game against Young Boys.
- Stream on ESPN+: LaLiga, Bundesliga, more (U.S.)
"Twist in the ankle. We didn't want to take risks with him. He didn't feel comfortable," Guardiola said. "He'll be back maybe Tuesday, but maybe next Sunday."
Haaland pulled up in discomfort when making a run in the box in the first half. City did not confirm which ankle the Norway striker hurt.
Haaland has scored 13 goals in all competitions this season, including two in last week's 3-0 win against Manchester United.
He hit the post with a header before being substituted against Bournemouth.
Jérémy Doku inspired City to a win, scoring one and creating four more as the defending Premier League champions moved to the top of the table.