Underwood, 23, told police he "wanted to go to Jesus" after he was detained for kicking and denting a car and asking passers-by for a gun on Wednesday. Underwood was taken into custody and hospitalized, police said.
The name of the hospital is not being disclosed by police, Coral Springs police dispatcher Elizabeth McDaniel said Saturday.
Underwood, who is intensely religious, suffers from bipolar disorder, which causes him to display manic and depressive behavior, according to his agent, Bob Huebner. He also tried to kill himself in 1999 by cutting his throat in Lansing, Mich.
Police detained Underwood after residents reported that he jumped into their cars.
Coral Springs resident Lorrie Thomas, 49, was driving Wednesday when she said Underwood walked in front of her Chevrolet Astro van.
"It was very disturbing," Thomas said. "He thrust his hip out to me, expecting to be hit. When I stopped, he was right at the front of my van."
Thomas told police Underwood looked at her after she stopped and just walked away. Thomas then called 911 from a nearby pay phone.
Shortly afterward, Pompano Beach resident Carlos Almanzar was driving his Honda Accord to work when Underwood kicked the car, cutting his knee in the process, police said.
Angry that Underwood had dislodged his rearview mirror and dented his car, Almanzar, 23, drove back to confront the former Miami Dolphins player.
"I thought he just kicked it for the hell of it. Then he told me he wanted to die," Almanzar said. "He said it was what the Bible wanted him to do."
Cowboys' officials were not immediately available for comment Saturday. A team spokesman on Friday told the South Florida Sun-Sentinel in Fort Lauderdale, that the Cowboys had no comment.
The Minnesota Vikings drafted Underwood in the first round in 1999, but he quit in training camp, saying his heart wasn't in football. A short time later he changed his mind and signed with the Dolphins, but was injured in his first preseason game.
A few weeks later, on Sept. 26, 1999, Underwood went to Lansing, where he repeatedly yelled "I'm not worthy of God" before he used two steak knives to cut his throat at the home of his girlfriend and their 17-month-old twins, police said.
Underwood later spent two months in proective care and was released from the Dolphins in December 1999 after he escaped from a psychiatric care facility in Sunrise. He was later found at his mother's home in Philadelphia.
Despite his troubles, the former first round pick by the Minnesota Vikings found a job with the Cowboys, who signed him in March. Underwood amassed 22 tackles and had four sacks this season.
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