Chelsea have warned fans a seating issue could prevent some from attending their Premier League opener against Crystal Palace on Saturday.
The club have been replacing seats in the Shed Upper, Lower Stand and the Matthew Harding Lower Stand with rail seating at Stamford Bridge.
However, their supplier is unable to guarantee the Matthew Harding Stand will be completed for the match.
The club said blocks eight, nine, 14, 15 and 16 will potentially be affected.
Chelsea, who won the Super Cup on Wednesday, say they are unable to say exactly how many fans may be impacted and will make a definitive announcement on Friday at 15:00 BST.