After a number of racers questioned the value of taking part in the Silverstone test on July 17-19 because they could not work on car set-up, motor racing's governing body issued a note to teams at the Nurburgring about what is and is not allowed.
Although the original stipulation still stands that race drivers can only take part in the test if they are not involved in car developments, the FIA has agreed that racers taking part will now be allowed to work on car balance with the new tyres.
A spokesman for the governing body told AUTOSPORT: "We can confirm that, as only one specification of tyre will be available for the test, it will not be necessary for the teams to satisfy us that race drivers are taking part for the sole purpose of testing tyres for the appointed tyre supplier."
Following discussions in the Sporting Working Committee meeting at the Nurburgring on Wednesday, it has already been agreed that race drivers can only take part in one full day of testing.
Teams do, however, have the option of splitting their race driver mileage into two half-days.
Jenson Button was one of several drivers who had questioned the value of taking part of the test if he was not allowed to even work on car set-up, which had appeared likely before the FIA clarification.
"If it is just running one type of tyre then it is not tyre testing, it is just running around - so I don't think I will do it," said the McLaren driver. "I have driven Silverstone enough."
McLaren sporting director Sam Michael said that despite the FIA clarification his outfit was still unsure about which drivers it would run.
"I don't know yet," he said. "Let's get through this weekend and work out if it is useful to have race drivers there, or we just do the test with the test drivers.
"They don't need any laps around Silverstone to learn the track, so it is what they [the racers] can contribute."
Pirelli has revealed that it will be bringing two different compounds to the test, with three sets of hard tyres and two sets of medium tyres available per car per day.