He said the injury happened during a doubles match with his wife against her daughter and son-in-law.
About three-quarters of the way through the first set, the former competitive tennis player hit the serve that injured his shoulder.
“Right after I hit the serve, I thought, wow, my shoulder hurts.”
Probst continued playing, but by the following set he could no longer hit a backhand without pain.
He sought treatment the following month and underwent an X-ray and ultrasound before seeing his orthopaedic surgeon, who recommended surgical repair.
An MRI showed a full-thickness tear of the supraspinatus tendon with 16mm tendon retraction, tendinopathy and muscle atrophy.
ACC declined cover in January 2025 based on advice from its clinical adviser, a physiotherapist, who said the recorded mechanism of injury – described as hitting the ball awkwardly and hurting his shoulder and, elsewhere, doing an awkward overhead shot and wrenching his shoulder – did not reflect unexpected high-energy force consistent with traumatic rotator cuff tearing.
The physiotherapist also pointed to tendon retraction, tendinopathy, muscle changes and Probst’s age, saying these were less supportive of a traumatic cause. Probst disputed the description, saying it failed to convey the force of the serve.
Probst has played tennis since childhood and estimates the serve was about 112km/h – much harder than other serves he hit during the match.
Before the accident he was active in sports, swimming three times a week, and had no shoulder problems. Following the injury, he stopped tennis, swimming, surfing and paddling and avoided pulling or lifting with his right arm.
Probst challenged ACC himself before engaging a lawyer.
ACC changed its original decision after Rob Probst challenged it. Image / ACC
“Because it was wrong,” he said of his decision to continue fighting.
“When people are trying to get away with something that is incorrect and take advantage of people’s unwillingness or inability to challenge stuff, that just gets me fired up.”
The review found Probst’s tear was caused by the February 2024 accident and not wholly or substantially by a pre-existing condition or degenerative process.
The reviewer found ACC’s clinical adviser had not considered the mechanism of injury as described by Probst and did not have the original ultrasound or initial physiotherapy notes when giving his opinion.
He also noted Probst experienced immediate pain, there was a distinct temporal connection between the accident and his symptoms, and Probst had been “incredibly active for his age” without shoulder problems before the accident.
The reviewer said the MRI report did not identify moderate or severe degeneration.
“Ultimately, [the ACC physiotherapist] has misunderstood the mechanism of injury, has commented without a full clinical picture, and has not provided any reasoning on why he considers that the injury was caused wholly or substantially by degeneration, with a no more than minimal contribution by the accident event,” the decision said.
The reviewer noted Probst’s orthopaedic surgeon had examined him, while the physiotherapist conducted a paper review, and found the surgeon better qualified to give an opinion on the tear.
ACC head of service operations Phil Riley said cases such as Probst’s could be clinically complex.
“Cases like Mr Probst’s, where ACC is assessing whether a condition was caused by an accident or degenerative changes can be clinically complex, and clinical professionals may reach different conclusions despite assessing the same information.”
Riley said treating specialists played an important role, but their advice was considered alongside other medical information, and ACC could seek further specialist advice.
He said ACC had worked with orthopaedic specialists to develop guidelines “to help support consistent and accurate decision making”.
“After assessing the available clinical evidence, including the guidelines, we were unable to determine that Mr Probst’s condition was caused by his accident.”
Riley said Probst provided additional information during the review hearing.
“We accept the reviewer’s decision and have approved cover and funded Mr Probst’s surgery.”
For Probst, the outcome was bittersweet.
“I was happy that the time and the money that I’d expended, and the mental effort had paid off, that you could prevail against an unjust decision.
“But it is bittersweet because it could have been done a year earlier and I could have risked further injury during that time period.”
The reviewer awarded Probst $1218.13 in review costs, but he was left with $3206.87 in legal costs after ACC’s contribution.
Riley said reviews were free to lodge.
“Clients do not need a lawyer and may choose to represent themselves or be supported by an advocate, family member or other representative. ACC may contribute towards review-related costs.”
He said ACC offered a free Navigation Service providing independent guidance and support.
ACC figures show the proportion of rotator cuff surgery purchase orders declined rose from 22% in 2024 to 35% in 2025. Across all orthopaedic surgery, it rose from 18% to 26%.
Probst said he decided to speak publicly because he had heard from other people who believed their ACC claims had been wrongly declined.
His advice to somebody who believed ACC had got their case wrong:
“Challenge it.”