Valtteri Bottas was taken to the medical centre after crashing out of second practice for the Austrian Grand Prix.
Bottas lost control of his Mercedes at 130mph through the left-handed sixth corner before slamming into the barriers.
The Finnish driver sustained serious damage to the front of his Mercedes in the accident.
Bottas emerged from his cockpit before heading to the on-track hospital after he triggered an impact of more than 25G.
Bottas's incident was the second flashpoint at the Red Bull Ring after Max Verstappen also crashed out.
The Dutchman was taking on the penultimate corner when his Red Bull snapped away from him.
Verstappen spun backwards into the barriers, writing off the rear of his car. Like Bottas, he would play no further part in the session.
There was drama for Sebastian Vettel, too, who produced an almost carbon-copy of Verstappen's mistake, but avoided any damage, the German coming to a halt before the barriers. He managed to limp back to the pits in his Ferrari.
It was Vettel's team-mate Charles Leclerc who set the pace, the Monegasque finishing a third of a second faster than anybody else.
Mercedes have won every race this season, but Leclerc's pace will provide the Scuderia with the hope they can finally challenge the all-conquering Silver Arrows this weekend.
Bottas' time before his accident was good enough for second, with the Red Bull of Pierre Gasly third in the order.
Lewis Hamilton, who heads into Sunday's race with a commanding 36-point championship lead over Bottas, topped the time charts in the opening running, but could finish only fourth later in the day.
The world champion, who is bidding for his fifth successive victory after dominating in France last weekend, finished 0.443 sec down on Leclerc.
Vettel, whose running was compromised by his spin, ended the day down in eighth.
McLaren are enjoying something of a resurgence this year, and Carlos Sainz posted the fifth quickest time. The Spaniard was within half a second of Leclerc.
His team-mate, British teenager Lando Norris, finished 10th, more than four tenths off Sainz.
George Russell again held the advantage over his Williams team-mate Robert Kubica. Russell was an eye-watering 1.3 sec faster than the struggling Pole.