Fernando Alonso has admitted that he fully understands the FIA's decision not to allow him to race this weekend.

"I tried until the last minute to race in Bahrain after the accident in Australia," he wrote on his Instagram account. "(They) have been hard days logically after such an impact, but until the last second I try to race to help the team after the incredible work they have done this week.

"I understand the position of the FIA doctors and now I will try to help my teammate (Stoffel Vandoorne) to make the most of the weekend. Thanks to everyone at McLaren."

Speaking at the official press conference, the Spaniard shed further light on the issue, revealing that he has several cracked ribs and that there are fears another crash could puncture a lung.

"It's understandable, I respect the decision," he told reporters. "I was ready to race, or at least practice, but they have been painful days. I was ready to work through this pain somehow in the car and make sure I could race, because at the end of the day the pain is manageable, if you don't think too much. But there are some others risks the doctors think."

Asked if he will be fit in time for China in two weeks, he replied: "It's not a hundred percent. There will be another test that I need to do in the next eight or ten days, after that test the FIA will evaluate again.

"Last week, Sunday, I was OK," he continued, referring to the day of the accident in Melbourne. "Some knee pain, but not big things. I had the green light from the doctors to leave the track, everything was OK.

"On the Monday, I had a little bit of overall pain, but nothing too serious. Then I flew back to Spain and the pain was similar, maybe more, so I decided to go for a proper check, a scan. I had a small pneumothorax on the lung so we took the advice from the doctors to relax at home.

"We repeated the scan last Monday and the pneumothorax has gone but I have some rib fractures so because of that there is some risk of driving and the g-forces could move (the ribs) into the lung.

"It is not like a broken leg or arm where you can deal with the pain, in the chest, where there are organs, we cannot do much more."

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