F1 cars are flying in the Bahrain GP. Fernando Alonso is not.

When the McLaren driver emerged seemingly unscathed from his accident with Haas F1 driver Esteban Gutierrez during the Australian Grand Prix, observers exclaimed it was a miracle he survived, Now, with the FIA discovery this week that Alonso’s carbon fibre seat broke at shoulder height after sustaining forces over 46G, the fact that he was able to crawl from the steaming wreckage without a scratch seemed too good to be true.

It was. Following mandatory FIA medical tests prior to the Bahrain Grand Prix this week, Alonso was found to have suffered broken ribs on his left side and a pneumothorax — a buildup of air between the lung and chest wall. Further, after consultation with FIA medical officers, it was ruled he is physically unfit to race this weekend; he‘ll be replaced by McLaren’s reserve driver, Belgian rookie Stefan Vandoorne. The 2014 GP2 Champion, Vandoorne will be making his Formula One racing debut.

There is a two-week break between Bahrain and the third round of the F1 championship in Shanghai, but Alonso will need to sit out that round as well if there remains a risk of compounding the injuries. Due to the extreme cornering G-forces and the nature of Alonso’s driver’s seat, a fractured rib might move into his lung. Alonso will face further FIA tests late next week to determine if he is physically able to race in China on April 17.