Nash, a two-year NFL veteran, was 24.
Agent David Canter confirmed his client's death, as did Denver team officials.
"The Broncos family has suffered a great loss with the passing
of Damien Nash," coach Mike Shanahan said from Indianapolis, where
he was attending the NFL's scouting combine along with general
manager Ted Sundquist. "I am stunned and deeply saddened by this
tragedy, and send my deepest condolences to Damien's family."
Canter, who is attending the annual NFL scouting combine in Indianapolis, was contacted after ESPN.com received reports of Nash's death from people close to other players who had participated in the basketball game. During a telephone interview, Canter, who was unaware of the incident, received a call from Denver officials confirming Nash's death.
"It's true," an obviously distraught Canter said. "It's true. I don't know what more to say right now, OK?"
Details of the incident were not yet available, and an official with the St. Louis police said an investigation was in its "very earliest" stages.
The proceeds of the event were to benefit the Darris Nash Find A Heart Foundation, which raises money for heart transplant research. The foundation was created last month after Darris Nash, 25, the older brother of Damien Nash, received a heart transplant.
Former Missouri receiver Sean Coffey was at the event with Nash
and told the St. Louis Post-Dispatch there was no indication
anything was wrong.
"Everything was normal. ... We were playing around at the game.
... He was fine," Coffey told the newspaper. "I give my best to
his family. This is crazy. I can't believe this is happening. It
was the first time I had seen him in a couple of years. I can't
believe he's gone. I'm so happy I got to see him one last time."
Lee Baker, who was teammates with Nash at Coffeyville Community
College in Kansas, was supposed to have dinner with Nash after the
basketball game. One of Baker's friends received a call that Nash
had collapsed a short time after leaving the event.
"We still don't know what happened. He looked in great shape.
He had four 3-pointers [in the game]. He had a big smile on his
face. There was no indication" anything was amiss, Baker told The
Associated Press. "He was a great guy. It's hard to believe. I
want to think I'm dreaming. I was looking at him today, and
thinking how proud I was of him. I was so happy for him."
One of Baker's final memories of Nash was of him holding his
infant daughter after the game.
"I feel fortunate to have met him," Baker said. "At the game,
you saw the looks on people's faces and how much they appreciated
A former University of Missouri standout, Nash entered the NFL as a fifth-round choice of the Tennessee Titans in 2005. He played three games with the Titans as a rookie, and then signed with Denver as a free agent last August. In his one season in Denver, he appeared in three games, rushing 18 times for 66 yards.
"The Denver Broncos organization is once again struck with
profound sadness over the tragic loss of one of our players," team
owner Pat Bowlen said in a statement. "This is a tremendous
tragedy and our hearts go out to the entire Nash family."
Nash is the second Broncos' player to die since the end of the 2006 season. Two-year veteran cornerback Darrent Williams was shot to death in a limousine after leaving a Denver-area nightclub Jan. 1.
Senior writer Len Pasquarelli covers the NFL for ESPN.com. The Associated Press contributed to this report.