Williams expects to find itself "a bit on the back foot" when it goes testing next year as a result of it not being able to take part in next month's post-season F1 test in Abu Dhabi.
Save for Williams, teams will stay on after the final race of the 2021 season at Yas Marina where a two-day young drivers' test will take place the following week.
In addition to putting young rookies through their paces, teams will also have the opportunity to sample once again F1's 2022 18-inch wheels and Pirelli tyres as fitted to their modified mule cars.
However, Williams does not have a mule car at its disposal, having declined for financial reasons to modify one of its existing chassis to suit F1's 18-inch wheels. The British outfit will therefore not participate in the December test.
"Unfortunately we won't be doing anything," said Dave Robson, Williams' head of vehicle performance.
"We won't be running there as we don't have a mule car and that stops us from running at the test.
"My understanding is if you don't have a mule car then you are not entitled to do the test. So we won't be there."
Robson admitted that Williams will head into 2022 with less knowledge than its rivals, but reckons the team will be able to catch up on its deficit in short order during winter testing.
"We know that the mule car would have been beneficial but unfortunately, at the time we had to commit to that, we just didn't have the resource to do it," explained Robson.
"It was a decision that was made an awful long time ago and we can't do anything about it.
"What will we ultimately lose? We will start winter testing probably a little bit on the back foot I would think.
"But I would hope that if the car is running well, we should be able to catch up quickly.
"We would like be at the test but we are not. Ultimately though, we won't be far behind once the races start."