Fernando Alonso has confirmed that fractured ribs will keep him out of this weekend's Bahrain Grand Prix following his accident at the first race of the season in Melbourne just under a fortnight ago.

The Spaniard was forced to withdraw from the Sakhir round following a medical evaluation on Thursday morning, with McLaren immediately naming reserve driver Stoffel Vandoorne as his replacement. The nature of Alonso's injuries, however, remained a popular topic of conversation as the double world champion met the press later in the day.

"Last week, I was okay on Sunday [after the Australian Grand Prix], some knee pain but nothing bigger, and I had the green light from the doctors to leave the track," he revealed, "On Monday, I had a bit of overall pain, but nothing too serious, but, when I arrived back in Spain, there was a little bit more so we decided to do a proper check..

"I had a small pneumothorax on the lung so I took doctors' advice to rest and then retook the scan last Monday. The pneumothorax is gone, more or less, but I have rib fractures and, because of that, there is the risk of driving because F1 has a unique position in the car and the G-forces could move the fractures into the lung. So, it is not like a broken leg or broken arm, where you can deal with the pain. This is in the chest and we cannot do much more."

Alonso, who missed the season-opener in 2015 after crashing in testing, insisted that he had tried everything he could to be able to take to the track in Bahrain this weekend, and said that he would be staying on in Sakhir in an effort not only to help his replacement, but also continue to learn about the development of the MP4-31.

"I'm a little bit disappointed, obviously," he admitted, "We want to race. We are competitive drivers - we like competition and love the sport so, when you come here and you cannot even try, it is always sad.

"It's understandable and I respect the decision. I tried until the last moment to be able to race and at least to try in the practice. There's been some painful days, with some pain at home, but I was ready to go through this pain in the car somehow and make sure I could race.

"At the end of the day, the pain is manageable if you don't think too much, [but] there are some other risks the doctors think about. It's a risk factor, I understand that, and to minimise everything is the logical thing. I'm a little bit sad for that, but it's the only way to go.

"Now I want to stay here for the weekend, help Stoffel, because it is a big opportunity for him, and help the team because I am very thankful for the job they did last week. I want to learn from the outside how the team prepare the race, the actions around the new qualifying system, the race itself... The team told me I will fly home, but I said 'no way'! I want to hear the cars, I want to see the new updates on the car and how they work. I want to get involved in everything from the outside because it could help me on the inside at the next race."

Whether he is fit to race in round three is another matter, however, and the Spaniard revealed that he will have another medical test ahead of the Chinese Grand Prix.

"It's just a question of time for the rib to [knit] together and, for this, the next ten days should be okay, but we cannot guarantee it," he noted, "It may be ten, it may be five, it may be twelve...

"It's not 100 per cent [that I'll be fit], so there'll be another check I have to do in the next 8-10 days. After that, the FIA will evaluate me again as they did here."