Chelsea captain Reece James is set to miss "a few weeks" after injuring his hamstring in training this week, says manager Mauricio Pochettino.
The 23-year-old has started rehabilitation after doctors assessed the injury.
James started in Chelsea's season-opening 1-1 draw with Liverpool at Stamford Bridge on Sunday before being substituted in the 77th minute.
"It's a sad moment because he's our captain," said Pochettino.
"He was so excited and full of energy to be our captain. We are going to assess him day by day.
"For sure he's going to [come back] stronger than he was.