He was the league's top goalkeeper last season, and could be headed for another All-Star Game this year. He's become universally respected by his peers, admired by fans and beloved by children who look up to him. He's also come a long way from the gambling addict who nearly threw away his career.
Nielsen recently updated and released an autobiography he wrote in Denmark that details the ups and downs of his career for an American audience. Its title, , lays out everything he went through in black and white, some of the stories cringe-worthy, others humorous and endearing.
"When I was reading the book after it was all done, I felt like I was reading about another person completely," Nielsen said while lounging in the Sporting KC practice facility. "It was eight, nine years ago, and that's a pretty good sign that all that stuff is behind me now."
Nielsen speaks in a measured voice, choosing his words carefully not so much because of a language barrier - he speaks perfect English, in part because he played with teams in England growing up - but because he wants to ensure he's relaying his thoughts forthrightly and honestly.
He also wants to drive home the point he's a different person now, and he's hopeful that maybe his story will help others overcome gambling addiction.
The National Council on Problem Gambling estimates that two million people in the US meet the criteria for pathological gambling, and up to six million more would be considered problem gamblers.
"The question I get a lot from the parents is, 'Can my kids read the book?' Well, of course they can," Nielsen said. "There are no bad words. The story is about me being down, coming up, being down, having a problem with gambling, and I actually think kids could learn a lot from it."Whereas he once went on weekend trips to Las Vegas and never left the casino floor, he now pulls youngsters out of the stands and allows them to take shots at him 40 minutes before a game.
Hard to imagine a big league ballplayer having a game of catch with a kid during warm-ups.
He'll pull over his car when he sees children kicking a ball in some leafy park, call up his wife, Jannie, and tell her that he'll be a little late for dinner. He'll hop out and stand in goal, a professional taking shots from five- and six-year-olds just for fun.
"We all have our back story, you know?" Sporting KC coach Peter Vermes said. "I think the difference is normally most people don't write a book about themselves, so it's not out there.
"The difference with him is he's comfortable with himself," Vermes said. "We all make mistakes here and there and we have to move on with life, because nobody is mistake-free. The greatest thing about Jimmy is he has a good aura about him, right? When I talked to him on the phone I could tell this is the kind of guy I want on my team."
The road that brought Nielsen to the middle of the US was a bumpy one.
He was scouted by Manchester United and other top European clubs from a young age, and most thought he would be the heir to Denmark's greatest goalkeeper, Peter Schmeichel. But by the time he was on the Danish under-21 team, he was being dropped for missing curfew.
The reason? A late night spent at the roulette wheel.
All the gambling finally caught up to him about a decade ago, when an inability to pay off his losses put a bookie out of business. Nielsen avoided bankruptcy with some help from his club at the time, and he managed to keep his family together thanks to his wife's grace.
"He's shared stories with me, both good and bad, some very intimate ones - different locations and things that happened and who he had to deal with," said one of his closest confidants, Sporting KC assistant coach John Pascarella. "To see all that in print, kind of interesting."
Indeed, it's all there in the book, but so is Nielsen's dramatic recovery.
After a failed stint with English club Leicester City, he started to wonder whether his career was over. But in January 2010, he got a phone call from Sporting KC, a club he'd never heard of in a city he barely knew existed in a league that was supposed to be for washed-up players.
He took the boldest step of his life by moving his entire family halfway around the world for a chance to keep playing the game he's always loved.
"I was told the MLS is a retirement league, when you move over there, you'll be done," he said. "Those people had no clue what they're talking about. Maybe it was that way 20 years ago, but if you're not on your toes here and you're not extremely fit here, you will not make it."
Nielsen made 10 shutouts his first season with what was then known as the Kansas City Wizards, and then went 12-8-11 the following year, when the club rebranded itself as Sporting KC.
Nielsen played every minute in the net last year, and his 0.79 goals-against average at the end of the regular season was a club record. He had 15 clean sheets , second-most in league history, and helped his team capture the US Open Cup and the Eastern Conference title.
"I think everyone appreciates how good he is," said Sporting Club CEO Robb Heineman, who wrote the foreword to Nielsen's book and remains one of his biggest supporters. "He's been rewarded in the recent past for his accomplishments and I think that's a good thing.
"When it comes time to replace Jimmy," Heineman said, "it's going to be a tough thing."
It'll be tough for Nielsen, too.
He'll be 36 in August, so he knows his years of playing high-level soccer are limited. But he also knows that he's found his sweet spot in Kansas City, where he's part of a community that has been willing to forgive the faults of his past to embrace the man he's become. "It hasn't been what I expected," he said. "It's a lot better than I ever expected."
This article appeared in the South China Morning Post print edition as: All bets are off for Sporting Kansas City's gambling goalie Nielsen
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