DENVER (KDVR) — Former running back Ronnie Hillman, who helped the Denver Broncos win the 2015 Super Bowl, has died, according to his family. He was 31.

Hillman’s family posted on his Instagram that the former Broncos player was diagnosed with Renal Medullary Carcinoma in August.

“RMC is a rare but highly aggressive neoplasm form of cancer that primarily affects young African Americans with sickle cell trait,” his family wrote on Instagram.

On Wednesday, Hillman’s family said his treatment had not been successful and he quietly passed away.

Hillman’s family left this message on his Instagram accompanied by a photo of the beloved running back smiling in his Broncos jersey:

It is with heavy hearts that we announce the passing of our beloved son, brother and father, Ronnie K. Hillman Jr. 

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

We as the family, appreciate the prayers and kind words that have already been expressed. We ask that you would give us time to process our feelings as we prepare to lay our precious RJ to rest.  

More information will be forthcoming.

With love, The Family

Hillman was the leading rusher for the Broncos in 2015, starting 10 out of 16 games and running for 863 yards on 207 carries. Seven of those were touchdowns.

Hillman was a third-round pick from San Diego State in 2012. He spent four seasons with the Broncos before spending his 2016 season with the Minnesota Vikings and the then-San Diego Chargers.