It might be called serious, but it could also be declared extremely lucky.
A following horse landed on Phelan's jaw after he'd fallen from Yangming, trained at Rotorua by his father Craig.
"It wasn't a pretty sight," said stipendiary steward John Oatham.
Craig Phelan said his 21-year-old son's attitude to the injury did not accurately reflect the seriousness.
"All he wanted was his cellphone and the equipment to stay in touch with his mates on Facebook.
"Shaun has been going steady with Welsh jockey Emily Farr, who returned to Wales a few weeks ago.
"By the time I called Emily she'd already heard about the fall on bloody Facebook and she was freaking out."
Farr is on a scholarship from Oxford, where she studies equine science and had a handful of rides in New Zealand before returning home last month.
Shaun Phelan was due to travel to Europe, where he had been guaranteed rides from the stable of Emily Farr's parents, who train jumpers in Wales.
In-form Kayla Veenendaal crashed heavily at the third fence in one of the early hurdles races. She lay on the track for a lengthy period but concussion was her only issue, creating a mandatory three-week stand-down.
Irishman Niall Quinn injured two vertebrae in his fall, but the injury is not one of those associated with paralysis.
Cody Singer has an injured shoulder joint which is likely to keep him out of action for six to eight weeks and Aimee Taylor, whose mount Bold Mariner was brought down when Singer and It's A Monty fell short of the winning post in the last race, has an issue with a knee. "It's not bad and I hope to ride later in the week if I can get a clearance," she said.
Craig Phelan knows how lucky his son has been.
"The fall was at the top of the home straight as everyone knows. At home, I can't run the width of the drive up to our stables, but when I saw what had happened I sprinted from the birdcage to the fall and I reckon I broke the track record.
"When I got there I thought: 'How the hell did I do that?'."
When master trainer Colin Jillings retired and was asked who he admired in horse racing, he said: "Jumps jockeys - the bravest of the brave."
Craig Phelan is on his team.
"If we go to war all I want in my trench is a whole bunch of jumps jockeys.
"They're one tough bunch.
"Well, tough or mad, I'm not quite sure."