Dubai-based triathlete Rich Holland, aged 29, was struck by a car in the early hours of October 11, as he rode his bicycle from his home to the city’s new cycling track.
His injuries include multiple broken bones, two punctured lungs and severe brain stem damage that has left him in a "semi-coma" in Dubai's Rashid hospital.
Mr Holland’s doctors say it could be many months or years before his condition will improve significantly.
The young triathlete had set his sights on racing in the Ironman 70.3 race in Phuket this year after completing the Laguna Triathlon in 2010.
He competed regularly in triathlons and duathlons around the world, and represented South Africa in the 2007 World Duathlon Championships in Hungary.
This weekend's half-Ironman race in Phuket would have formed part of the celebrations for his 30th birthday, on November 30.
But now, with Mr Holland unable to race – and facing a very long and difficult recovery – a group of his friends from Dubai have embarked on a fund-raising mission for their mate.
Andrew MacRae, Edward Hawkins, Brett Smyth and other competitors will don "Back On Your Bike" wrist-bands as they "race for Rich" in Phuket on Sunday.
The three athletes aim to raise money for the “Back on Your Bike” trust, set up Mr Holland's family to raise money for his treatment and recovery.
Mr Holland's family estimate it will cost up to $US 1.7 million to pay for his hospital treatment in Dubai and later rehabilitation in his family home in Cape Town, South Africa.
Their initial fund-raising target is $US 150,000, to cover his immediate medical costs and next few months of rehabilitation.