High school football player Ryan Gillyard dies during morning workout

A high school freshman football player died following a morning workout Saturday, according to the Philadelphia Enquirer.

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Ryan Gillyard

Ryan Gillyard, a 15-year-old running back and linebacker for St. Joseph's Prep (Philadelphia), suddenly collapsed after warm-ups on the school's practice field, according to the report.

He was rushed to Temple Hospital where he perished.

"It's just a sad day," St. Joseph's Prep Athletic Director Jim Murray told the newspaper. "People are mourning the loss of a young man."

School spokesman Bill Avington told the Enquirer: "From what I've been told by others, he was a great kid, loved by his classmates and teammates."

The cause of death isn't known as of yet. Grief counselors will be at school starting Monday, according to Avington.