Penn State football letterman and NFL Hall of Fame running back Franco Harris died overnight, according to the Associated Press. He was 72.

No cause of death is known at this time.

Harris played at Penn State for three years under Joe Paterno from 1969-1971. He tallied 2,002 rushing yards and 24 touchdowns in Happy Valley before being selected in the first round of the 1972 NFL Draft by the Pittsburgh Steelers.

Harris’ death comes just days before the anniversary of his “Immaculate Reception,” which is often considered among the most iconic and improbable plays in NFL history. The Steelers were scheduled to honor the play on Friday and his jersey number was set to be retired at halftime of Saturday’s game against the Raiders.

“Franco Harris was among the very best Penn Staters—a shining example of true greatness. He rose to dizzying heights but was rooted in service to others,” wrote Penn State Trustee Jay Paterno. “His loyalty was steadfast in good days but also through the tempest winds of adversity. We will always love & respect him.”

The native of Fort Dix, New Jersey, won four Super Bowls and earned nine Pro Bowl bids en route to an illustrious professional career. He spent all but one of his 12 years in the NFL in Pittsburgh.

Following his playing career, Harris founded Super Bakery, which focused on creating nutritious food for children, with Lydell Mitchell, his teammate at Penn State. In 1996, Harris and Mitchell also revived Parks Sausage Company, which was the first Black-owned business to be listed on the New York Stock Exchange.

“We lost one of the GREATEST HUMAN BEINGS EVER…” former Penn State linebacker LaVar Arrington wrote. “I want to be sad but the Nittany Lion in me is so proud to call him not only a friend, alum, letterman…he was FAMILY!!”

Harris is survived by his wife, Dana Dokmanovich, and his son, Dok Harris.