Fernando Alonso has been refused his place on the starting grid for the Bahrain Grand Prix after failing a medical test following his high-speed crash in Melbourne.
The Spaniard, 34, underwent a series of tests at Bahrain's Sakhir Circuit medical centre on Thursday, but it was deemed that he will be unable to take part this weekend on "safety grounds".
It is the second time in Alonso's career that he has been sidelined for a race after he was ruled out of last year's season-opener in Australia following his mysterious crash in pre-season testing.
A statement released by the FIA, the sport's governing body on Thursday, read: "Following an examination undertaken this morning at the Bahrain International Circuit Medical Centre, it has been decided that McLaren Honda F1 team driver Fernando Alonso should not take part in this weekend's Bahrain Grand Prix.
"Two sets of chest CT scans were compared and it was decided that there was insufficient resolution of the signs to allow him to compete on safety grounds.
"A repeat chest scan has been requested before the Chinese Grand Prix and the results will be considered before allowing him to race there."
McLaren have since confirmed that their reserve driver Stoffel Vandoorne will deputise for Alonso this weekend.