When the Washington Capitals defenseman thinks back to his overtime goal that won the 2010 World Junior Championship for the United States against Canada, the passing of the decade strikes him almost as much as the significance of that moment to his career.
"Time is really flying," Carlson said. "It's kind of sad in a way."
A lot of good things happened since then, though.
"Yeah, obviously," Carlson said. "But they're over."
The 30-year-old laughed after he said that. No doubt, there are more big moments ahead for him, perhaps at the end of this season.
But he's right. It doesn't seem like that long ago that the Capitals selected Carlson with the No. 27 pick in the 2008 NHL Draft.
This season, he's the frontrunner to win the Norris Trophy as the League's top defenseman and is headed to the 2020 Honda NHL All-Star Game at Enterprise Center in St. Louis on Saturday (8 p.m. ET; NBC, CBC, SN, TVAS). It will be his second straight All-Star Game appearance.
Video: BOS@WSH: Carlson one-times feed from Backstrom
"Probably last year was more special just being my first and everything, but it's a cool honor," Carlson said. "It's a fun weekend for the most part and I'm looking forward to going back."
Carlson's selection was a no-brainer. He's first among NHL defensemen with 60 points (13 goals, 47 assists) in 49 games, putting him on pace to finish with 100.
That would make him the first defenseman to get 100 points in a season since Brian Leetch of the New York Rangers had 102 in 1991-92 and the first with at least 90 points in a season since Ray Bourque of the Boston Bruins had 91 in 1993-94.
"He's a special player, and he's getting better every year," defense partner Michal Kempny said. "For me and a lot of people, he's the best defenseman in the NHL right now."
It's been a gradual progression for Carlson to reach this point and, in a way, it all began with that goal against Canada in the world junior championship game on Jan. 5, 2010.
"It gave me a lot of confidence," Carlson said. "It kind of changed my outlook on a few things just with that confidence, and it made a difference for my game, especially that year."
There's no question it was an important goal.
Skating in on a 2-on-1 rush with forward Derek Stepan on his right, Carlson was planning to pass before deciding at the last instant to shoot, beating goalie Martin Jones to the short side to give the U.S. a 6-5 victory and its second world junior championship.
"Certainly, scoring the goal in overtime to win the gold medal was a heck of an experience, especially the way he did," said Dean Blais, coach of the 2010 United States team. "He looked off and made a shot, but he'd done that a lot of times in his life."
Hearing Carlson's quote about what the goal did for his confidence produces some surprise among those who know him and have watched him develop.
"He was never short on confidence before," Capitals goalie Braden Holtby said.
Holtby, who was selected by Washington in the fourth round (No. 93) of the 2008 draft, has been with Carlson almost every step of the way. They won the Calder Cup together with Hershey in the American Hockey League in 2010 and the Stanley Cup with the Capitals in 2018.
"He's never doubted that he would be a top defenseman," Holtby said. "Even when he first came up here, his goal was to be a go-to guy and not to just wear the sweater. So he's always had that natural in him."
Video: WSH@LAK: Carlson scores 100th career NHL goal
Assistant general manager Ross Mahoney, who was director of amateur scouting when the Capitals drafted Carlson, remembers watching Carlson as a 17-year-old when he tried out for the United States team for the 2007 Ivan Hlinka Memorial Tournament. Mahoney also tracked his progress in the United States Hockey League with Indiana in 2007-08 and London in the Ontario Hockey League in 2008-09.
Carlson turned pro after his season with London and helped Hershey win the 2009 Calder Cup, getting three points (two goals, one assists) in 16 playoff games. He spent most of the first half of the 2009-10 season in Hershey, but he played in three NHL games with Washington in November before being sent back to the AHL and leaving to play for the United States at the world junior tournament in Saskatoon, Saskatchewan.
"It's interesting because John had accomplished so much (before that)," Mahoney said. "But maybe when you're playing in the world junior with your peers and you have the success that he did, I'm sure it did give him a lot of confidence."
Carlson has always believed in his abilities but said he had same the doubts many young players experience before they establish themselves in the NHL.
"That was a big jump," Carlson said. "It's a big jump for almost anybody to make it here and to be a quality, consistent player here."
Scoring the world junior winning goal brought Carlson recognition -- he was voted to the all-tournament team -- and a realization that he belonged. He briefly rejoined Hershey after the tournament before being called up to Washington.
That season, Carlson had six points (one goal, five assists) in 22 NHL regular-season games and four points (one goal, three assists) in seven games in the Stanley Cup Playoffs. He also had 39 points (four goals, 35 assists) in 48 regular-season games with Hershey, earning a spot on the 2009-10 AHL all-rookie team, and finished off his season by getting seven points in 13 AHL playoff games to add another Calder Cup title to his world junior gold.
Carlson began the following season with Washington and has remained in the NHL since.
"I think it was just an important time," he said. "I was young and trying to find my way and I think in a lot of ways (the goal) gave me a lot of confidence to take elsewhere that year to make a step in the right direction. It's obviously a nice memory to have, a fun experience to be a part of, but most importantly it was kind of that springboard for my career in different ways."
There have been other important moments in Carlson's career since then. Todd Reirden's arrival in Washington, initially as an assistant in 2014 before being promoted to coach before last season, was one of them.
Reirden immediately recognized Carlson's skill and his ability to respond to challenges. Together they charted out a series of goals designed to help him reach the next level. Those included winning the Stanley Cup, being selected to play in the All-Star Game and increasing his standing in the Norris Trophy voting until he wins it.
Video: WSH@SJS: Carlson cranks a slap shot past Jones
Carlson helped the Capitals win the Cup in 2018 with 20 points (five goals, 15 assists) in 24 playoff games after leading the League's defensemen with 68 points (15 goals, 53 assists) in 82 regular-season games. He topped that with an NHL career-high 70 points (13 goals, 57 assists) in 80 regular-season games last season, was selected for the All-Star Game for the first time and climbed from fifth in the Norris voting to fourth.
Carlson has been equally reliable defensively, usually playing against opponent's top lines, and his ability to break the puck out of the defensive zone with accurate outlet passes often starts Washington's transition game.
"The plan we've been able to see through here is something where every year he left for the summer with a different something he was going to work on and how we were going to change his game for the next year to become more of a factor," Reirden said. "Obviously, now you're seeing the final product. But he's a confident player who trusts his game and his teammates trust him."
Carlson was rewarded after the Capitals won the Stanley Cup with an eight-year, $64 million contract he signed on June 24, 2018. Some players struggle trying to live up that kind of contract, but Carlson has only gotten better.
He's had a similar reaction since being named an alternate captain at the start of this season. Carlson has approached the role like he does playing, studying leaders from other sports, such as New England Patriots quarterback Tom Brady (he's a Patriots fan though he moved from Marlborough, Massachusetts to Colonia, New Jersey when he was 5) and what they say to help him learn how to lead more effectively.
But the suggestion that being an alternate captain has helped him elevate his play brings a reserved response.
"I don't think it hurt," Carlson said. "Especially early on in the season, I think it got me more engaged and just the way things ended last year everything seemed to blend together in a positive kind of direction. But I don't know if I'd know whether it's helped or hurt. Obviously, it didn't hurt, so let's go with the other one."
Although he might always appear confident, he said he goes through rough periods like most. He considers his ability to get past those stretches quickly, "one of the assets in my career.
"I think particular spots in your career are big," Carlson said. "You learn from your mistakes. You learn from letting yourself go down a certain path or thinking about things too seriously, not serious enough. You're constantly reflective."
Carlson has had plenty to reflect on since that overtime goal against Canada. If he's sad about those 10 years flying by, he also appreciates where they've taken him and what could be next.
The Capitals (33-11-5) are in first place in the Metropolitan Division and hoping to make another run at the Stanley Cup.
"There's a lot of room for improvement for us and I think we're in a pretty good position," Carlson said. "So, it's easy to look ahead and try to iron out things that we want to accomplish to get ourselves in the best position, whether that's mentally, physically standings-wise or what have you, to make a good run."