An autopsy of the junior high school student was being conducted in Rapid City, South Dakota.
Wallem said preliminary findings show that Sorenson suddenly died from peritonitis.
The Mayo Clinic explains that peritonitis "happens when the thin layer of tissue inside the abdomen becomes inflamed." Peritonitis can be caused by infection by bacteria – typically when someone has liver disease or kidney disease. Other health conditions that cause peritonitis are liver cirrhosis, appendicitis, stomach ulcers, diverticulitis (inflammation of pouches in the digestive tract), Crohn's disease, and pancreatitis. Peritonitis can also be caused by a "rupture, inside an organ in the abdomen."
Wallem told the Cowboy State Daily, "We are assuming it’s (from) an injury related to a sporting event."
The coroner said he is "focusing on the injury in the sporting event as the cause of peritonitis," but added that if the determination isn't supported by medical evidence, then "we will continue to look at other answers."
Wallen said that additional tests by a forensic pathologist were being conducted.
Sorenson's obituary said the 17-year-old died "due to complications from injuries sustained playing basketball."
"Max had an incredible work ethic and was very disciplined. His focus was evidenced by his achievements at school, on the basketball court, at church and in his social activities," the obituary read. "Even more important than those successes were his welcoming smile, kind eyes, curly locks and loving personality, which made friendship with him easy and comfortable and was felt by everyone."
His parents said he was a "smart, hard-working student, he maintained a perfect 4.0 GPA." Max also played golf, and was a wakesurfer and wakeboarder.
"Max loved his savior and the gospel of Jesus Christ. He attended early-morning seminary and served as the bishop’s first assistant in his Gillette ward as well as other leadership positions in the church," his parents said.
"Max loved basketball and in particular he loved his teammates, coaches, and the chance to travel to various locations to play," the obituary continued. "He was a member of the varsity basketball team at Thunder Basin High School and looked forward to helping the Bolts to a repeat Wyoming state championship in 2023."
Sorenson was a 6'3" guard weighing 175 lbs. who played on the Thunder Basin High School basketball team.
The Thunder Basin boys basketball team paid tribute to the teen who tragically died.
Thunder Basin High School basketball coach Rory Williams said, "I'm not going to remember Max as the basketball player. I'm going to remember Max as the kindest young man I’ve ever been around. He was just so genuine, authentic; his personality was contagious."
Williams said Sorenson's sudden death was a "freakish medical situation."
During the recent Hoop City Classic basketball tournament, the Thunder Basin High School boys basketball team honored Sorenson by wearing his #3 jersey. The Harrisburg High School boys basketball team also paid tribute to Max by wearing Sorenson's #3.