Former driver Martin Brundle - who was Schumacher's team-mate at Benetton:
Let's hope Michael Schumacher's ski shunt is not too bad and that he's totally fixable. He's a crazy brave skydiving/bike racing daredevil
— Martin Brundle (@MBrundleF1) December 29, 2013
Hours later, when the full extent of Schumacher's injuries had become clear, he urged:
Come on Michael, give us one of those race stints at pure qualifying pace to win through, like you used to. You can do it.
— Martin Brundle (@MBrundleF1) December 29, 2013
British driver Jenson Button:
My thoughts are with Michael Schumacher at this tough time.. Michael more than anyone has the strength to pull through this.
— Jenson Button (@JensonButton) December 29, 2013
Felipe Massa, the Brazilian driver whose injury brought Schumacher back to F1 in 2009, posted a picture of the pair embracing on Instagram, with the Portuguese message: "I'm praying for God to protect you, brother!"
Schumacher returned to the sport racing for Mercedes in the 2010 season.
Jean-Eric Vergne, Jules Bianchi, and Max Chilton also weighed in, offering best wishes and wishing him a quick recovery.
Romain Grosjean, who finished second to the German legend in the 2012 Nations' Cup:
All our thoughts to Schumi and his family ! Hope you will recover soon. #legend #Schumi
— Romain Grosjean (@RGrosjean) December 29, 2013
Heikki Kovalainen, who tussled with him on the track in 2004 and 2007:
I heard Schumacher had a skiing accident, I hope it's not too serious and he makes a full recovery soon! #legend
— Heikki Kovalainen (@H_Kovalainen) December 29, 2013
Scottish F1 driver Paul di Resta:
Terrible news about MSC, thinking of him and his family. Hoping for better news and that he can pull through #getwellsoon
— Paul Di Resta (@pauldirestaf1) December 29, 2013