D.C. United striker Eddie Johnson said "my health is more important" after announcing his retirement at age 31.
Johnson earned 63 caps for the United States national team, but a heart ailment curtailed a career that began when he was drafted by Dallas at age 16 in 2001.
He last played in MLS during last season's playoffs and reportedly had his contract voided in May, but D.C. United still honored him in a halftime ceremony during Sunday's 1-0 defeat to the Red Bulls.
"Today it finally hit me," Johnson told MLSsoccer.com afterward. "I'm very emotional. I want to thank D.C. United -- the whole D.C. United organization -- for making this all possible, making sure I was able to share this moment not only with the amazing fans here, but my loved ones and my friends and my two kids.
"At the end of the day, if you're going to go out in any way, shape or form, you want to be able to share it with the people that you love the most."
Johnson played five years for FC Dallas before moving to Kansas City. He was signed by Fulham in the Premier League before returning to MLS in 2012 with Seattle.
After Johnson expressed discontent over his contract, the Sounders traded him to D.C. United, who made him a designated player. He scored seven goals for D.C. last season, but he missed most of training camp this year because of the heart condition and never played again as he sought medical advice.
"That was the whole rollercoaster," Johnson said. "Looking and visiting and seeing different types of doctors to see if there was any hope. At one point, there was a lot of hope, everything was looking positive. But the condition that I'm going through wasn't where they wanted, where their expectations were.
"At the end of the day, my health is more important. I don't want to be running around on the field and have something bad happen to me."
There was uncertainty surrounding when the Sounders knew of the striker's athletic heart syndrome, which eventually led to the league cancelling his contract, according to the Washington Post.
"Eddie had many outstanding accomplishments during his career and was a valuable member of the team during his time with D.C. United," said general manager Dave Kasper. "He will be missed but always remembered as he moves on beyond the playing field."
Johnson scored 71 of his 90 goals in his club career in MLS, and added 19 international goals for the U.S., including a winner over Mexico that secured the Americans' place at the 2014 World Cup.
He made two appearances at the 2006 World Cup but was left off the final squad for the past two tournaments.
With his playing career behind him, Johnson said he hoped to coach children in his native Florida.
"Soccer has a lot of buzz in Orlando right now and I'm looking forward to the next chapter in my career as far as my role in soccer," he said. "It's kind of funny: During my career, I always found it tough training hard every day, then going and doing an appearance or coaching kids. So I always took the [option of] signing autographs or speaking to youth.
"But I've developed this love for coaching kids. I've got a lot of friends back in Florida who have youth clubs and academies going, and I've been able to shadow them ... Being a director of coaching or coaching kids myself, it's something I'm really looking forward to."