Britain's Anthony Davidson has broken two vertebrae following a huge accident five hours into the Le Mans 24 hour race.
His Toyota flipped into the air and crashed heavily into a barrier after contact with a Ferrari.
The former F1 driver suffered breaks to his T11 and T12 vertebrae - injuries which are expected to heal in "approximately three months".
Toyota added that Davidson would remain in hospital until Monday.
The Hertfordshire born driver tweeted from his hospital bed: "Well that was a big one! Lying in a French hospital with a broken back wasn't what I had in mind at this stage in the race..."
The 33-year-old had just taken over from Sebastien Buemi at the wheel of Toyota's TS030 Hybrid entry when his car made contact with the LMPGTE Ferrari, driven by Italy's Piergiuseppe Perazzini, on entry to the corner at the end of the Mulsanne straight.
In an earlier statement the team said: "Doctors at the circuit have confirmed that Anthony is suffering from shock and back pain.
"However, there are no signs of any injuries and he is walking and talking with no problems."
Perazzini walked away from the accident, but Davidson was treated by medical staff at the scene.
The race continued behind the safety car for more than 30 minutes as marshals reconstructed the tyre wall, which had been badly damaged by Davidson's car.