Toyota driver Kazuki Nakajima has been diagnosed with a broken vertebra following his accident in practice for this weekend's Spa World Endurance Championship round.
The injury came to light after the ex-Formula 1 driver was transferred from the circuit medical centre to a local hospital for further tests in the wake of the incident, which happened on a wet track when he ran into the back of the Audi driven by Oliver Jarvis.
Nakajima, who was ruled out of the second round of the WEC earlier on Thursday, will remain in the hospital in the nearby town of Verviers while the injury is assessed.
No timescale for his release or transfer to another medical facility have been released.
"It's unbelievably disappointing but there's nothing I can do now, " said Nakajima.
"I will just focus on coming back as soon as possible."
A statement from Toyota read: "Further medical analysis in the coming days will determine if there are consequences beyond this weekend's event."
The injury to Nakajima means that reigning WEC champions Anthony Davidson and Sebastien Buemi will race as a duo in Saturday's Spa 6 Hours, as they did in four of the eight rounds in last year's series.
Kamui Kobayashi, Toyota's test and reserve driver was not available because he is in Japan.
The #1 Toyota TS040 HYBRID is being built up around a new monocoque overnight and is scheduled be ready in time for Davidson and Buemi to take part in final free practice on Friday morning.
Nakajima ran into the back of #8 Audi R18 e-tron quattro, which had just left the pits, at the end of the Kemmel Straight in heavy spray.
"There's not much I can say about the accident," said Nakajima
"I was on the straight and suddenly through the spray there was a car right in front of me; I had no time to react."
Footage from Spa's CCTV and the car's on-board camera has revealed that reports of an LMP2 car moving over for Nakajima before the impact are erroneous.