Mercedes GP team principal Ross Brawn has been forced to miss this weekend's Spanish Grand Prix on doctors' orders.
The team has announced that Brawn will be absent from the event, but gave no details on his illness.
He is expected to return to lead the team at the next event in Monaco.
Technical director Bob Bell will take charge of the factory Mercedes squad in Spain this weekend, alongside chief executive Nick Fry and Mercedes motorsport vice-president Norbert Haug.
Seven-times world champion Michael Schumacher, who has worked with Brawn for the majority of his F1 career, says that his absence will offer the team an extra challenge.
“Naturally we will miss him, be sure about this,” said Schumacher.
“But he will be in contact with us and support us in his maximum way. We had to deal with his absence during some of the Ferrari days and will have to deal with it here this weekend,”.
“But as you can imagine with all his experience and knowledge it is going to be certainly a challenge for us.”
Brawn has an array of F1 world title to his name, including championship success at Benetton and Ferrari as technical director, before leading the team that beared his own name Brawn GP to the 2009 championship.
See below for Speedcafe.com's Spanish Grand Prix Race Guide