Keenan Davidse hit nine birdies to card a sensational 63 and take a one-shot lead after the opening round of the Joburg Open on Thursday.
Oosthuizen's freaky injury, however, opens up the door for red-hot compatriot Dylan Frittelli, who won in Mauritius last week, to try and secure his place at the 2018 Masters at Augusta National.
The Sunshine Tour, who co-sanction the tournament along with the European and Asian tours, posted a photo on social media on Wednesday of Oosthuizen's bruised and swollen fingers.
"I'm obviously very happy", said the 28-year-old. "I was in hospital for about four days so I'm very chuffed today", Davidse told reporters. "I'm just out here to have fun, but obviously pleased to have played well".
"When I played at Simola (recently) my little boy was sick with a bad chest, then my wife had the flu and then I got the flu, and lost a lot of weight". It's always nice leading a big tournament and especially the Joburg Open. "I got a good number down today and will take it one day at a time", he said.
He is joined by James Morrison, Sebastian Heisele and South African trio Jared Harvey, Erik Van Rooyen and Ockie Strydom. I have a friend who is a member‚ so I played a round with him on the Firethorn course.
The Joburg Open‚ which is normally played on the two courses at Royal Johannesburg and Kensington‚ has been moved to Firethorn and Bushwillow courses at Randpark this year.
"I think some guys maybe lean too much on being familiar with the golf course but for me, if I walk on to that first tee and I'm feeling fresh, ready to go". "I therefore had no expectations coming into this week".
Nathan Kimsey, last season's champion at the Qualifying School Final stage, is also tied for eighth after he birdied four of the last seven holes on the Bushwillows layout to post a 65, but Mauritius Open champion Dylan Frittelli has ground to make up after a disappointing one-under 71.