Urso, 22, was pronounced dead at 1:50 a.m. at Grant Medical Center in Columbus, Franklin County Coroner Dr. Jan Gorniak said. An autopsy is scheduled for Monday.
Police were called to a bar in the city at about 12:50 a.m. and Urso was taken from there to the hospital, The Columbus Dispatch reported. Police officials did not immediately return messages from The Associated Press seeking details on the circumstances.
Urso played in six games this season and was sidelined by groin surgery in May. He was not with the team Saturday for its 1-0 loss to D.C. United in Washington, team spokesman Marco Rosa said.
The team withheld detailed comment, and the hospital said privacy laws ruled out any comment.
"The thoughts and prayers of the entire Columbus Crew and Hunt Sports Group are with the Urso family in this time of need," a team statement said.
Major League Soccer Commissioner Don Garber said the league would hold a moment of silence at games Sunday. "Major League Soccer mourns his death and sends our condolences to his family," he said.
Urso was in his first season with the Crew. In a team profile last month of Crew rookies, he said he was frustrated with injuries.
"To go from getting picked up late in the draft, to starting and contributing, and then to be out completely and hurt — it's really frustrating. Injuries are just a part of (soccer)," he said.
A native of Lombard, Ill., Urso played on North Carolina's NCAA title-winning team last fall and for the U.S. under-17 World Cup team in 2007.
With the NCAA title, Urso said it helped erase years of frustration for him and the other UNC seniors.
"My whole college career has been awesome, but there was something extra about this team," Urso said. "To cap it off with this is something I'm going to remember the rest of my life."