Injured Williams star Valtteri Bottas is "impatient" to return to the cockpit of his car this weekend in Malaysia after being forced to miss the opening round in Melbourne.
The 25-year-old Finn sat out the 2015 season opener because of soft tissue damage in his lower back sustained in qualifying.
Bottas travelled straight from Australia to Indonesia, where he posted photographs on Twitter of himself swimming.
"Progress is being made," he said, "and every day is a good step forward. Can't wait for Malaysia!"
His manager Didier Coton also posted a photo of Bottas doing weight work in the gym on social media.
Hakkinen suggests seat was to blame
Double world champion Mika Hakkinen, who is also a member of Bottas' management team, suggested that the driver's seat may have contributed to the injury.
"In my own career," he told the Ilta-Sanomat newspaper, "I had a lot of seats made and each was slightly different to the other.
"It is not easy to find a completely perfect seat."
Rumours suggest that if Bottas does not race in Malaysia, he will be replaced by Pascal Wehrlein, who is the reserve driver for Williams' engine supplier Mercedes.