The 39-year-old was airlifted to hospital with his co-driver Dale Moscatt after Grant's silver lotus reportedly "left the road at speed" during the Lake Mountain sprint stage of the Australian Tarmac Rally Championships.
Denyer is currently recovering at The Alfred hospital in Melbourne while his co-driver is awaiting an operation for his suspected broken leg.
Grant's wife Chezzi was at home in Bathurst at the time of the accident with the couple's two young daughters, Sailor and Scout, while Grant's father flew to his side.
Speaking to News Corp Australia, Chezzi claimed that the “freak accident” will not stop her husband from racing.
“Strangely enough, I sat down last Thursday to start writing an article for my blog about what it’s like to be married to a daredevil, but I couldn’t find the right words...it just wasn’t working...so I stopped writing it. It’s been a hard day, but I have never tried to talk him out of it and I wouldn’t because I know how much he just loves it.”
She said her husband was “so cautious” as a driver.
“He doesn’t really have accidents and I don’t really worry. He’s told he’s fine, it was just a freak accident.”
Chief operating officer of the Lotus racing team, Richard Gibbs said: “we are reviewing on board footage and electronic control unit [dashboard] to find out the cause of the accident. Our first concern is the welfare of our drivers. Our CEO, Lee Knappett was on the scene with Dale and is now with him at Royal Melbourne [hospital].”