Sergio Perez will not race in Sunday's Monaco GP after crashing heavily in Saturday's qualifying.
The Mexican will remain in Princess Grace hospital overnight as he begins his recovery from a concussion and thigh injury suffered when he collided with a barrier at high speed.
"First and foremost we are obviously relieved with the reports that Sergio is okay. It's always very worrying for a team when you see an accident of that magnitude, so it's good to hear that he is fundamentally okay," said Sauber technical director James Key.
"We are looking into what happened. There is no indication at the moment from the data we have seen that there was a problem with the car. But we have to talk to Sergio to investigate further what happened."
"Of course we are very relieved that Sergio wasn't seriously injured," added team owner Peter Sauber.
"Up to the accident he was doing very well in qualifying, and also better than expected as he had outperformed all his direct competitors."
With Perez absent, Kamui Kobayashi will be Sauber's only representative on the Monaco grid.
