McLaren reserve driver Stofffel Vandoorne will step into Alonso's McLaren during the Bahrain Grand Prix weekend as the Spaniard was found to be insufficiently recovered from his crash at the Australian Grand Prix two weeks ago.
"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," FIA press officer Matteo Bonciani confirmed.
Following the rejection by the FIA, McLaren confirmed that Belgian Stoffel Vandoorne will be replacing him at Bahrain. The team went on to recall the reigning GP2 champion from his duties in Japan in preparation for the Super Formula season.
As for Alonso, the target is now on a racing return at the Chinese Grand Prix as he continues to recover from broken ribs and a pneumothorax - a partially collapsed lung.
"A repeat chest scan has been requested before the Chinese grand prix," the FIA’s Bonciani said, "and the results will be considered before allowing him to race there."
Alonso said to reports at Bahrain that it is indeed not sure yet if he'll be allowed to race at China.
"It’s not 100 per cent," Alonso said of his chances. "It will be another test I need to do in the next 8 to 10 days. For this weekend, I was ready to go through the pain somehow and make sure I could race, or at least try, but the first thing is safety and so I understand (the decision)."