Former F1 driver Kamui Kobayashi is set to replace Kazuki Nakajima in the Le Mans 24 Hours after the Toyota regular was injured in an accident in practice at Spa on Thursday.
Toyota said the Japanese driver will "need a miracle" to be fit for Le Mans.
"Kazuki is in good spirits but he will be out for a while for sure," said team director Rob Leupen.
"We are supporting him and will help him to get fit as soon as possible.
"We will need a miracle for Kazuki to be at Le Mans, but you can't rule it out completely. I think though that we will get Kamui (Kobayashi) over to Europe as soon as possible. He has been informed to be ready."
Motorsport.com has learned that Toyota will test before Le Mans at Spa later this month and that Kobayashi will be involved with the team in Belgium.
Toyota believes that Nakajima's accident yesterday will not drastically affect its Spa weekend after the team built a new TS 040 monocoque overnight.
"We have a lot to do for sure but for here we will be fine with the new car which is just a fresh tub with most of the running gear from yesterday bolted on," confirmed Leupen.
"The production department is now looking at all options and we have a meeting here tomorrow to finalise all options."
Toyota has an in-house composite department in Cologne who will be working flat out between now and Le Mans to ensure the team has sufficient chassis and spares.
The chassis damaged in the Nakajima accident is being evaluated for repair, as a fresh tub takes a minimum of six weeks to create. The team is expected to produce new monocoques after Le Mans for the remainder of the season.
The team had already lost a tub at a Paul Ricard endurance test last month but this one was planned to be 'retired' anyway.