San Francisco offensive guard Thomas Herrion passed away early Sunday morning following Saturday night's preseason game with the Denver Broncos.
Herrion collapsed in the locker room moments after the game, was given CPR and rushed to St. Anthony's Central Hospital in Denver. He was pronounced dead three hours later.
"This is a colossal tragedy for the 49ers and the entire NFL community, the team said on their official website.
"We still do not know all of the details. However, our thoughts and prayers are with the entire Herrion family."
Herrion was a first-year player with San Francisco after playing college ball at Utah. He spent part of last season on the San Francisco and Dallas practice squads and also played this season with the Hamburg Sea Dogs of NFL Europe.
The cause of death has yet to be determined.
Herrion was 23 years old.
49ers offensive lineman dies following game
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