Williams has postponed its first planned track run of its 2019 car, which had been scheduled for this weekend ahead of the first pre-season test in Barcelona.
Teams often opt to carry out one of its two filming days the weekend before the opening test in order to do a proper shakedown of the car. The rules give every team two days, each allowing 100 km of running, across a season.
Williams had planned to run its 2019 car, the FW42, at the Circuit de Catalunya on Saturday, but instead will use the time to maximise time at the factory before testing begins at the same venue two days later.
"As anyone would expect, we have had an extremely aggressive engineering programme over the winter," Williams said. "As such, we have taken the decision not to run our car during our filming day this weekend in order to allow the team to maximise the time at the factory before we head to Barcelona for the first day of the test on February 18th."
There is also uncertainty about whether Renault will make its own planned filming day this weekend.
At the launch of its new car, the R.S.19, on Wednesday, Renault team boss Cyril Abiteboul said: "I think we've maybe gone a bit over the red line, that's why really my thoughts are already with production who are massively working to get the parts out of the door for us to be ready and testing as we speak. I think next year we will have to be a bit more conservative because it's not just performance, it's also reliability.
"You don't want to turn up and have to shakedown your car and suddenly realize that there is something that is not working. So it's a balancing exercise, we've been a step too far, maybe we'll have to review it for next year."