Toyota driver Anthony Davidson will miss this weekend's Mexico City round of the World Endurance Championship courtesy of a rib injury sustained in testing.
The 37-year-old Briton bruised his ribs in an accident during a two-day test with Toyota at Magny-Cours in mid-August.
He had been expected to be fit to take part in the Mexican event this weekend, but has been withdrawn from the race as a precaution after feeling discomfort during Thursday's 90-minute test ahead of the free practice sessions.
A Toyota spokesman told Autosport: "Anthony is basically alright, and if there was a championship at stake he would be in the car.
"But we didn't want to take a risk ahead of Austin [the next WEC round on September 17].
"It can be very hot in Austin and we will definitely need three drivers there."
Davidson added: "It is disappointing to come all the way here and then not be able to race but it's the right decision.
"I wasn't comfortable in the car this morning and there is no point to take any risks, especially with Austin coming up."
Davidson's withdrawal means Sebastien Buemi and Kazuki Nakajima will drive the #5 Toyota TS050 HYBRID as a duo in Saturday's six-hour race.
The news on Davidson follows an accident for the sister car in the extra test session on Thursday morning that has ruled it out of the opening two periods of free practice.
The monocoque was damaged when Stephane Sarrazin crashed under power out of the final corner and the car is now being rebuilt around Toyota's spare tub in time for final practice and qualifying on Friday.