Hillman was in August diagnosed with renal medullary carcinoma, a rare form of cancer, according to a statement posted to his social media on Wednesday.
Former teammates such as Derek Wolfe and Orlando Franklin had expressed how dire Hillman's health was recently, saying Hillman had been moved into hospice care. Franklin took to social media to ask, "please pray for Ronnie Hillman ... this ain't fair, please god, please."
Wolfe said that Hillman had liver cancer and contracted pneumonia as well.
The list of current and former NFL players to pass away in 2022 is long, ranging from Hall of Famer Franco Harris, who died Wednesday morning at age 72, to former Steelers and Washington Commanders quarterback Dwayne Haskins, who was killed in a tragic accident in April at age 24.