Ronnie Hillman, Super Bowl-winning running back for the Denver Broncos, died Wednesday at the age of 31, according to a post from his family on his Instagram page.
Hillman was diagnosed in August with renal medullary carcinoma, a rare form of cancer, according to a statement posted to his social media on Wednesday.
His family’s message read: “It is with heavy hearts that we announce the passing of our beloved son, brother and father, Ronnie K Hillman Jr.
“Ronnie transitioned quietly and peacefully today in the company of family and close friends.”
Medullary renal cell carcinoma is a very aggressive cancer that mainly affects people with sickle cell trait (SCT). It was not immediately clear if Hillman himself had SCT.
San Diego State University (SDSU), Hillman’s alma mater, posted a tribute on its football team’s official Twitter.
“Gone too soon,” reads alongside an image of Hillman.
“We will miss you, Ronnie,” the message ends.
On the school’s website, SDSU athletic director John David Wicker wrote, “We are saddened to learn of the passing of Ronnie Hillman. Ronnie helped resurrect San Diego State football during his two seasons in 2010 and 2011 and has recently been part of the program offering wisdom and insight.
SDSU head coach Brady Hoke also wrote a tribute saying, “Our deepest condolences go out to Ronnie’s family.
“Even though I was only able to train him for one season, I will remember him as an excellent teammate and a hard worker. Ronnie always came to practice with a smile on that face and his passion for the game was contagious. He will always be an Aztec for life.
After two stellar seasons at SDSU where he scored 36 touchdowns, Hillman was drafted by the Broncos in 2012, helping the team to the Super Bowl in 2014 and 2015, according to NFL.com.
The team was victorious in the latter against the Carolina Panthers after a season in which Hillman was their best running back – posting for 863 yards and seven touchdowns.
Hillman spent time with the Minnesota Vikings and Los Angeles Chargers during the 2016 NFL season, before signing with the Dallas Cowboys ahead of the 2017 season.
He never played for the Cowboys, having been released by the team shortly after signing.
CNN has reached out to the NFL and the Broncos for comment.