Valtteri Bottas says modifications have been made to his car ahead of the Malaysian grand prix.
The Finn got clearance from FIA doctors on Thursday to return for Williams this weekend in Malaysia, after tearing a disc in his lower back two weeks ago.
His manager, Mika Hakkinen, speculated that a problem with his seat may have caused the problem over the bumps in Melbourne.
"We have a good idea what caused it," Bottas confirmed at Sepang, "and have changed the seat and pedal positions.
"My back is now in more of a neutral position."
He said he is confident the problems will not arise again, and denied speculation that surgery to completely correct the issue will be necessary.
"I am completely pain free," said Bottas, "at least in normal kind of stuff and we will see when driving."