Connor Cosgrove found out on Sept. 14, 2010, that he had acute lymphoblastic leukemia (ALL). It is a pediatric form of blood cell cancer that rarely shows up in 19-year-olds.

“You normally find ALL in young kids and there is a very good chance for survival,’’ Cosgrove said. “The older you are when it occurs, the higher the risk for the patient.’’

Cosgrove was extremely high risk. He was undergoing chemotherapy on the same afternoon of the diagnosis.

“They took a biopsy and my bone marrow was 90 percent leukemia,’’ Cosgrove said. “The first 30 days are critical and the treatment is very aggressive. If there’s not a positive response, the end of the host can come as quickly as four weeks.’’

That’s a creative euphemism — “host’’ — for the patient in leukemia treatment. In other words, if the poisons being pumped into the body don’t have an early effect, the person can be dead within a month.

Cosgrove survived. Most of him, anyway.

He had started at 6 feet and 185 pounds, with aspirations to make it as a walk-on receiver with the Gophers. After 30 days of chemotherapy and doses of medication, he was on his way to losing 45 pounds and becoming a rail-thin 140-pounder.

Once the shock of that first month was over, Cosgrove started to contemplate what was happening to him. Three years later, he regrets his early reaction to this mightiest of challenges.

“I was an angry kid,” Cosgrove said. “A lot of people reached out, and I pushed most of them away. I was encouraged to reach out to Zach Sobiech, the young folk singer from Stillwater who was dealing with a pediatric cancer. I wouldn’t even do that.”

Sobiech died in May, at 18, after four years with osteosarcoma, a bone cancer.

Alexis Maciej, Cosgrove’s nurse practitioner at the university’s Amplatz Children’s Hopsital, observed his attitude for a time and then got him the emotional help to turn it around and “thrive with cancer.”

Cosgrove’s transformed attitude made his fight with cancer much more public, particularly in the fall of 2012. That’s when 60 members of the Gophers football team shaved their heads in support of pediatric cancer research.

Cosgrove had grown back his flowing locks by last fall. The head-shaving came about after Cosgrove told a few of his Gophers friends about a scene at Amplatz in September 2012.

“There were twin girls — 3 years, tops — and one had cancer and one did not,’’ Cosgrove said. “The little girl with cancer had lost her hair because of chemo. So her sister who wasn’t sick … she shaved her head so that her twin would not feel bad.

“Those two little girls walking down the hospital corridor holding hands was the coolest thing I’ve ever seen.’’

Cosgrove witnessed endless scenes, both cool and sad, in his three years of being in and out of Amplatz while undergoing chemo.

His father, Kevin, had been hired as Tim Brewster’s co-defensive coordinator in 2009. That was the same year Connor enrolled at St. Cloud State. A year later, Cosgrove and offensive lineman Brandon Haney, his St. Cloud roommate, transferred to Minnesota and walked on with the Gophers.

“I was hoping to be one of those walk-on, possession-type receivers that have had some success with the Gophers,’’ Cosgrove said.

A white guy with some speed and good hands?

“Exactly,’’ he said.

Connor found himself waking up in sweat-soaked clothes most mornings that August. As a player who took pride in his hard work, he was hardly able to lift weights. He would jog from one sideline to the other and feel tired.

On Sept. 13, 2010, a fever that he had encountered some nights was still with him in the morning. Susan Hecht, a team physician, sent him to the university clinic for blood work. A day later, he was undergoing treatment for leukemia.

Connor’s first pal at Amplatz was Nicholas Koenig.

“He was a little guy, 3 or 4, and from a family of big Gopher fans,’’ Cosgrove said. “Tim Brewster was at the hospital to see me every night after the chemo started, and he met Nicholas, and Coach Brew came back with all this Gopher stuff for him.

“It was a difficult time for Brewster and his coaches, including my dad. Everyone was thinking they would be fired, but for the next few weeks, Coach Brew was back to visit Nicholas on Mondays. He would put the little guy in a play wheelbarrow and push him through the corridor. They would both get joy from that.’’

Cosgrove paused and then said: “Nicholas is gone now. I don’t think it’s a story Tim Brewster would want me telling, but he was a better guy than he’s remembered by many people here.’’

Kevin Cosgrove wound up as the defensive coordinator at Akron in 2011. That staff was fired, and he landed at New Mexico as a linebackers coach for Bob Davie. Connor was among those convincing his mother, Shelly, to move to Albuquerque with Kevin in July 2012.

Connor stayed and continued the duel with ALL. He was given the powerful prednisone. He was given doxorubicin, known without affection by its recipients as “red death.’’

The bone in his shoulders, hips and knees is dead. His circulation is terrible, with his hands and feet freezing at all times.

His hair? That’s gorgeous.

“My hair always has been important to me,’’ Connor said. “When I lost my hair for a time, that’s was maybe the most depressed I’ve been in this whole process.’’

The chemotherapy process ended for Cosgrove on Dec. 13, after 1,185 days and what he estimated were 100 chemotherapy treatments. He and his friends celebrated the occasion because the intake of the cancer-killing poisons finally was over.

“There’s a specific timetable for chemo,’’ Connor said. “You can only take it for so long, and then it’s up to your body.’’

Cosgrove went to Albuquerque last Friday, to spend Christmas with his family. He wasn’t feeling well, went to a clinic and was found again to have very little in the way of an immune system. He was admitted to the University of New Mexico Children’s Hospital.

“They think it might be a virus,’’ Connor said by phone. “The worst part of this is we planned to be in Houston on Friday to watch the Gophers against Syracuse. Now, I’m going to miss the bowl game again. Same thing happened last year.’’

Connor Cosgrove didn’t sound as if he was feeling sorry for himself.

Only disappointed.