In Melbourne, the Hinwil based team's 68-year-old majority owner and founder tripped and fell at the paddock entrance, hurting his elbow and wrist.
Now, in Montreal on Thursday, the Swiss hurt himself again.
In the carpark near the Circuit Gilles Villeneuve, Sauber struck the top of his bald head on the hook of his hire car's rear trunk.
The four centimetre cut was treated by team physio Josef Leberer, according to veteran Blick newspaper correspondent Roger Benoit.
Sauber confirmed on Thursday that even his Melbourne injuries are not yet fully healed.
"But an operation would be too complicated," he said.
He hopes the Montreal incident is the last bout of bad luck for now.
"It's frustrating," said Sauber. "We have the best car in my 20 years in formula one and we are almost always giving away the results."