The cause of death for former Clemson running back C.J. Fuller was released by the Pickens County Coroner's Office on Tuesday.
Per Nikie Mayo of the Anderson Independent Mail, Fuller "died of complications related to a blood clot and deep vein thrombosis" that were "connected to a football-related knee injury."
Pickens County coroner Kandy Kelley said Fuller's deep vein thrombosis was caused by a blood clot in his leg that led to a pulmonary thromboembolism.
Kelley noted Fuller had knee surgery in September after suffering an injury at the J.B. Owens Sports Complex on Aug. 12.
Clemson confirmed Fuller died on Oct. 3 at the age of 22. He played three seasons with the Tigers from 2015-17, winning a national title as a sophomore in 2016.
Zola Fuller Beeks, Fuller's aunt, told Mayo the day after his death he had been experiencing chest pains prior to his death.
"He was conscious at one point, but when he got to the hospital, his speech was slurred," Beeks said. "Before we knew it, he was gone. We think it had something to do with a blood clot, but you just don't expect someone his age to be gone so fast."
After the 2017 season, Tigers head coach Dabo Swinney announced Fuller was going to graduate in the spring before transferring to a different school.
Fuller ran for 599 yards and four touchdowns on 147 carries in 35 games at Clemson.