The Pitt junior missed most of the 2015 season with a torn MCL and his struggle during rehab led to the discovery of a tumor in his chest.
"So I get some tests done. I got a tumor surrounding my heart, bro," Conner told rapper Mike Stud on his "Ya Never Know: ya know what I mean?" podcast. "My heart, I got tumors growing all around it ... Hodgkin's lymphoma. Doctor told me I had about a week left.
"He said, 'You got about a week. if you didn't get this treated, you had about a week, at the rate it was growing.'"
Conner underwent chemotherapy in the following months and revealed he was cancer-free in May 2016. He returned to play for Pitt the following season after enduring what he says was the "darkest" period of his life.
"The hardest part about the whole thing was telling my bros," Conner said. "I remember that like it was yesterday. ... How would they feel if their youngest brother was not here no more? How would they feel if their youngest brother died? I said I can't do it. I can't go."
The Pittsburgh Steelers drafted the 24-year-old in the third round of the 2017 NFL Draft. He broke out in 2018, totaling 1,470 yards from scrimmage and 13 touchdowns.