Tottenham manager Antonio Conte says that eight players and five members of staff have tested positive for Covid-19 at the club.
Spurs are scheduled to play Rennes in the Europa Conference League on Thursday and Uefa says "the match is due to take place as scheduled".
They then play Brighton on Sunday in a Premier League game which is believed to be under review.
"Now, for sure, we are a bit scared," Conte said.
"Every day, we are having more positives. This is not a good situation."
Following the game against Brighton, Tottenham face Leicester City on 16 December and Liverpool on 19 December in the top-flight prior to an EFL Cup quarter-final against West Ham on 22 December.