Williams has made the brutal decision to sideline Logan Sargeant in Melbourne.
Alex Albon, who is clearly the James Vowles-led team’s preferred driver, crashed heavily on Friday, damaging the so-called ’tub’.
And Williams, who even almost failed to take a single chassis to pre-season testing just a month ago following production delays, has not yet produced a spare - and one won’t be ready by the next race in Japan, either.
"It was a conscious decision to get the most out of the car," Vowles explained. "We knew we would pay for it in the event of a major accident.
"When we weighed up the risks, we factored that sacrifice in."
However, the sacrifice is being made by American Sargeant, who struggled as a rookie last year and is now fending off rumours Williams intends to replace him for 2025 with the Toto Wolff-backed junior Kimi Antonelli.
"This is the hardest moment I can remember in my career," Sargeant, 23, admitted.
Team boss Vowles was apologetic about the brutal decision.
"It’s unacceptable in modern day F1 not to have a spare chassis, but it is a reflection of how behind we were in the winter period and an illustration of why we need to go through significant change in order to get ourselves in a better position for the future," he said.
"We have made the call based on our best potential to score points this weekend."
Vowles said on Saturday that Albon’s crashed chassis will be fixed in time for Suzuka in two weeks.
"We have some updates and other parts planned, but I now have to use all manpower to repair the chassis," he said. "We will certainly have two chassis in Japan, but I don’t think there will be enough time to produce a third because we now have our hands full making the repairs."