Red Bull cancelled Sergio Perez's media commitments at the team's home Austrian Grand Prix on Thursday after the Formula One driver reported sick.
"He became unwell last night and is taking the day to rest to ensure he's in the best possible health for this weekend's race," the team said.
Perez is Max Verstappen's closest title rival but still a massive 69 points behind his double world champion team mate after eight races.
The Mexican needs a strong showing at Spielberg after failing to qualify in the top 10 or stand on the podium in the last three races.
This weekend is the second sprint event of the season -- Perez won the first one in Azerbaijan in April, going on to win the Sunday grand prix as well.
That race in Baku remains his most recent win and he has had only one podium finish since then while Verstappen has won the last four.
Earlier this month, Red Bull boss Christian Horner recognised that his team could win every race this season.
Friday features a single practice session and qualifying for Sunday's race with Saturday a standalone sprint day.