PC William Sampson - known as Billy - was due to go on trial on March 7 after he denied maliciously wounding a 16-year-old boy after the Barnsley FC and Sheffield Wednesday fixture on February 8, 2020.
The teenager was left with blood pouring from his head and following an investigation PC Sampson was charged nine months later.
It was revealed on Tuesday that PC Sampson was found dead in a property on Thorncliffe Lane, Chapeltown, last Friday afternoon.
A police spokesperson said: “We are incredibly saddened by news of Billy’s death.
“Our thoughts remain with Billy’s family and loved ones and they will be offered our full support.”