From ESPN:
Fernando Alonso to miss Bahrain Grand Prix on medical grounds
Fernando Alonso will not take part in this weekend's Bahrain Grand Prix after a medical examination on Thursday morning found he is not fully fit following his accident at the Australian Grand Prix two weeks ago.
Alonso spent 90 minutes in the medical centre at the Bahrain International Circuit on Thursday morning, which was followed by an FIA statement confirming chest scans showed he should not compete on safety grounds.
"Following an examination undertaken this morning at the Bahrain International Circuit Medical Centre, it has been decided that McLaren Honda F1 driver Fernando Alonso should not take part in this weekend's Bahrain Grand Prix," an FIA statement read "Two sets of chest CT scans were compared and it was decided that there was unsufficient 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."
The Spaniard suffered a terrifying accident at the season-opening Australian Grand Prix, which saw his car pitched into a barrel roll after making heavy contact with the wall. He walked away from the accident and completed media duties afterwards, but was required to go for more medical check ups in Bahrain before being cleared to race this weekend. He last missed a race last season after an accident in testing ruled him out of the season-opening Australian Grand Prix.
Alonso will be replaced by McLaren's reserve driver and GP2 champion Stoffel Vandoorne.