Tottenham Hotspur had a stomach bug before Sunday's home game against Burnley.
Dejan Kulusevski was one of four Spurs players who reported sickness on Saturday, Antonio Conte said.
Spurs substitute Kulusevski was fit after playing 72 minutes in Thursday's 3-0 win over Arsenal.
"We only had yesterday to prepare for the game but this is the schedule and we have to play," Conte told BT Sport an hour before kick-off.
"Yesterday, Kulusevski missed practise. He had a stomach ache.
"It wasn't just him, maybe a virus spread through the team."
"4 players yesterday but fine. Lucas Moura replaced Kulusevski in training.