Perez ruled out of Monaco GP

The Mexican was taken to the Princess Grace hospital on Saturday after crashing heavily against the barriers at the chicane, having lost control of his car under braking.

Perez escaped serious injury, but his concussion means he will be unable to race in the Monte Carlo event.

Perez will stay in hospital at least overnight.

"Of course we are very relieved that Sergio wasn't seriously injured," said Peter Saber.

"Up to the accident he was doing very well in qualifying, and also better than expected as he had outperformed all his direct competitors."

Technical director James Key added: "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.

"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."

The rookie's absence means team-mate Kamui Kobayashi will be the only Sauber in the race tomorrow.