Ronnie Hillman, a Super Bowl-winning running back for the Denver Broncos, passed away aged 31 on Wednesday, according to a post from his family on his Instagram page.

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.

The post from his family reads, “It is with heavy hearts that we announce the passing of our beloved son, brother & father, Ronnie K Hillman Jr.

“Ronnie quietly and peacefully transitioned today in the company of his family and close friends.”

Renal medullary carcinoma is a highly aggressive cancer that primarily affects people with sickle cell trait (SCT). It was not immediately clear whether Hillman himself had SCT.

San Diego State University (SDSU), Hillman’s alma mater, posted a tribute on their football team’s official Twitter.

“Gone way too soon,” it reads alongside an image of Hillman.

“We’ll miss you, Ronnie,” the post ends.

On the school’s website, SDSU’s director of athletics John David Wicker wrote, “We are saddened to hear about the passing of Ronnie Hillman. Ronnie helped resurrect San Diego State football in his two seasons in 2010 and 2011 and has recently been around the program offering wisdom and insight.”

SDSU’s head coach Brady Hoke also penned a tribute, saying, “Our deepest condolences go out to Ronnie’s family.

“Although I only got to coach him one season, I’ll remember him as a great teammate and hard worker. Ronnie always came to practice with a smile on this face and his passion for the game was contagious. He’ll 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 were victorious in the latter over the Carolina Panthers after a season where Hillman was their leading rusher – posting 863 yards and seven touchdowns.

Hillman spent time at the Minnesota Vikings and Los Angeles Chargers in 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. (CNN)

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