The Spaniard had fractured his ribs in the smash at the Australian Grand Prix with Esterban Gutierrez's Haas. With only two weeks recovery from the injury there is a small possibility that should Alonso have another crash this weekend he could puncture a lung.
The ratification means that McLaren Honda reserve driver, Stoffel Vandoorne will make his Formula One debut in Sakhir, a circuit where he has won at on his last two visits in GP2 with ART.
To race in Bahrain the 27-year-old has had to abandon the second pre-season test for Dandelion Racing in the build up to the 2016 Super Formula Season in Japan. The quick turnaround means that Vandoorne won't arrive in Bahrain until Friday morning.
The Belgian is highly regarded by many as a future star in Formula One after dominating GP2 in 2015 with seven wins and 16 podiums.
" I want to get involved in everything from the outside because it could help me at the next race."
"I want to race, I was ready to do my best because it is just pain and adrenaline but the doctors have said that I can't."
It is the second time in just over a year the double World Champion has been forced to miss out one of the opening races through injury, after his crash at testing in Spain last year.
Alonso will have more medical checks by the FIA before the Chinese Grand Prix in two weeks time but should the 34-year-old not be allowed to race in Shanghai then the Spaniard could be forced to retire from the sport.