Williams adjusts its F1 car after Valtteri Bottas's back problem

The Finn was passed fit after the FIA medical team inspected him on Thursday and will return to the cockpit for this weekend's Malaysian GP.

But to ensure that there is less stress on his back in future, the team has made changes primarily to the pedal positioning even though Bottas is still using the same seat he was using in Australia.

"We have a really good idea, so we have changed the seat and pedal position quite a reasonable amount," said Bottas.

"The back is in a more neutral position in the car, so there is less pressure for the discs.

"Now, I think we have got it right.

"I don't want to go into the details, but it's quite a big amount [of change] to make sure everything is in a neutral position with the back so when the compression comes, it goes to all the discs with similar pressures."

Bottas believes that, while he had no problems with the position of his body during testing, the bumpy nature of the Albert Park track put extra pressure on his back.

He is confident that there will be no repeat of the problem in the race, with doctors having ruled that the only limiting factor Bottas must face when driving is any pain that develops.

"At the end of last week, I could do something without any pain and during the weekend I could do some training - swimming and cross-training - without any pain," he said.

"We've been doing everything we can in this short space of time but luckily there was two weeks [gap] and I really feel confident about getting back in the car.

"It has healed really well and it's going to keep getting better and better all the time.

"I have no pain and the doctors have told me that the pain is going to be the limitation, not the safety."

Bottas confirmed that he was keen to race in Australia after initially suffering the injury in qualifying.

But he accepted the FIA's decision not to allow him to participate.

"It felt like someone put in a knife and then the pain was ramping up until midnight," said Bottas of the moment he suffered the injury under braking for Turn 13 on his final Q2 lap.

"Luckily it started to ease off and in the morning I would have been ready to race.

"I did pass the [medical] tests but they had all the access to the material we got from the hospital from the MRI and all that stuff and maybe they thought it's just better [not to race], which could be true.

"It was very disappointing not to be able to race but I have respect for the decision of the FIA."