Hazel Woods, the chief investigator for the Lincoln Parish coroner's office, said the cause of death was not yet known and an autopsy is pending. Ruston police Lt. Tim Parker said authorities are not investigating at this time and are awaiting the coroner's report.
"Tyrone was a valuable part of this football family," Bulldogs coach Sonny Dykes said. "This is a tragic, senseless loss, but he made a lasting impact on this team, university and everyone that knew him."
A roommate of Duplessis made the emergency call after the running back woke up with chest pain, Louisiana Tech spokesman Patrick Walsh said.
The 21-year-old Duplessis, a third-year student from New Orleans, recently completed his sophomore season of eligibility.
Dykes has informed his players of Duplessis' death and the team held a meeting to discuss it. The university has also made grief counselors available to the team.
"We were deeply saddened," Louisiana Tech president Dan Reneau said. "Tyrone was not only a valuable member of our football program, but much more importantly, he was a valued member of the Tech Family. This is a painful loss for our campus community and our thoughts and prayers are with his friends and family."
Duplessis played in two games last season as he sought to come back from a knee injury that sidelined him in 2010. As a true freshman in 2009, he had 70 carries for 277 yards and returned four kickoffs for 88 yards. That season, he ran for a career-high 75 yards on 14 carries against Hawaii. He also had 17 carries for 65 yards at then-No. 9 LSU, helping Louisiana Tech hold a 13-10 lead at halftime before the Tigers came back to win 24-16.
"Our thoughts and prayers go out to Tyrone and his family," athletic director Bruce Van De Velde said. "Tyrone was a special young man who was loved and respected by the Tech Family. He will be dearly missed, but I am sure his teammates and friends will honor and remember him through their commitment to fulfilling their potential."
Duplessis was recognized as an all-state running back at O.P. Walker High School, where he won a state championship in 2007.
He is survived by his parents, George and Mary, and two siblings, George III and Levoneshia Dixon.