The former Pro Bowl quarterback went into detail about his current health status in an interview with Cleveland Magazine this week ... when he explained he has had problems with his liver for years, but never really addressed it until he was diagnosed with cirrhosis roughly 16 months ago.

Kosar has been receiving treatment at University Hospitals in Ohio ... and his condition was described as "dire" at the start of 2024. Thankfully, it has since improved.

Dr. Michael Roizen -- one of the medical professionals helping Kosar -- told the outlet there is more than a 90-percent chance the Super Bowl champion will need a new liver ... and he's currently on a transplant list.

The former Miami Hurricanes superstar detailed his recent struggles ... saying his body gave out on him on Dec. 28, when the Browns hosted the New York Jets on Thursday Night Football.

"I really felt like I wasn’t going to make it home from the Jets game," Kosar said. "I sucked it up, though, and continued to avoid the doctors until the new year. Then I went into the hospital and got a massive blood transfusion."

"It was like -- 'How are you alive? How are you moving? Because your hemoglobin levels are so low.'"

Months later, Kosar was hospitalized for several days after flying to Las Vegas for the Super Bowl ... and continued to deal with the side effects of liver disease -- admitting he "felt like death" three months ago.

"E. Coli blood poisoning," Kosar said. "Heart trouble. And, I really thought I needed the liver transplant ASAP. I was in bad shape."

On top of the liver troubles, Kosar said he was diagnosed with Parkinson's by an independent NFL doctor that same month.

But, Kosar is putting a major focus on his body now ... and his docs say his test results are looking better.