One of the top players in the NHL, Karlsson has had many memorable moments since he was drafted by Ottawa 10 years ago.
[RELATED: Karlsson traded to Sharks by Senators]
Here's a look at some of the most important dates in Karlsson's career:
June 20, 2008: The Senators select Karlsson in the first round (No. 15) of the 2008 NHL Draft after he had 37 points (13 goals, 24 assists) in 38 games with Frolunda in Sweden's junior league.
Oct. 3, 2009: Karlsson makes his NHL debut and has his first point, an assist, in a 5-2 loss to the New York Rangers.
Dec. 19, 2009: Karlsson scores his first goal 21 games into his NHL career. It comes 2:55 into the third period against Minnesota Wild goalie Niklas Backstrom in a 4-1 win by the Senators.
April 14, 2010: In his first game in the Stanley Cup Playoffs, Karlsson, 19, has a goal and an assist in a 5-4 win against the Pittsburgh Penguins in Game 1 of the Eastern Conference Quarterfinals.
Jan. 30, 2011: Karlsson plays in his first NHL All-Star Game.
Dec. 16. 2011: With his third assist of the game, on Zenon Konopka's second-period goal in a 6-4 victory against the Penguins, Karlsson reaches 100 points in his NHL career.
Jan. 29, 2012: In his home rink, Karlsson plays in his second All-Star Game but does not get a point.
June 19, 2012: Karlsson signs a seven-year contract with the Senators, which runs through the 2018-19 season.
June 21, 2012: Two days after signing his contract, Karlsson wins his first Norris Trophy as the top defenseman in the NHL. He has 78 points (19 goals, 59 assists) in 81 games, 25 more than the next defensemen (Dustin Byfuglien and Brian Campbell).
Feb. 13, 2013: Karlsson sustains a lacerated Achilles tendon in his left leg when Penguins forward Matt Cooke's skate cuts him. He has surgery and is expected to miss 4-6 months.
April 25, 2013: Ten weeks to the day of the injury, Karlsson returns against the Washington Capitals. He has two assists, including the primary assist on Sergei Gonchar's overtime goal, in a 2-1 win.
Dec. 23, 2013: Karlsson's third point of the game, an assist on a goal by Kyle Turris in the third period of a 5-0 Senators win against the Penguins, is the 200th point of his NHL career.
Feb. 23, 2014: Karlsson wins a silver medal with Sweden when they are defeated by Canada 3-0 in the gold medal game at the 2014 Sochi Olympics. His eight points are tied for the tournament lead and he's named to the Olympic All-Star team and named the best defenseman in the tournament.
Oct. 2. 2014: Karlsson is named the ninth captain in Senators history, replacing Jason Spezza, who was traded to Dallas on July 1, 2014.
April 4, 2015: With an assist on Clarke MacArthur's first-period power-play goal, Karlsson gets his 300th NHL point in a 4-3 overtime win against the Capitals. Karlsson (393 games) becomes the fastest defenseman to reach the mark in 17 years (Sergei Zubov reached 300 points in 354 games, Jan. 11, 1998).
June 24, 2015: Karlsson wins his second Norris Trophy after scoring an NHL career-high 21 goals and leading defensemen in points with 66 in 82 games.
Jan. 31, 2016: Karlsson scores his first goal in an All-Star Game, a 4-2 win by the Atlantic Division against the Metropolitan Division in the semifinal in Nashville. The Atlantic Division is shut out 1-0 against the Pacific Division in the final game.
April 5, 2016: Karlsson's 100th NHL goal, and 80th point of the season, comes in the first period of a 5-3 loss to the Penguins.
Oct. 18, 2016: Karlsson scores with 13 seconds remaining in a 7-4 win against the Arizona Coyotes. It's the 102nd goal of his NHL career, moving him past Wade Redden for first among defensemen in Senators history.
Nov. 22, 2016: Karlsson joins the 400-point club with a second-period assist before scoring the game-winning goal 5:37 into the third period of a 4-3 win against the Montreal Canadiens.
Dec. 7, 2016: Karlsson has three points, and his second one, a goal at 7:19 of the first period of a 4-2 win against the San Jose Sharks, gives him 411 points, passing Redden for most among defensemen in Senators history. Karlsson reaches the milestone in 332 fewer games than Redden.
Jan. 29, 2017: In his second straight All-Star Game, Karlsson scores a goal but the Atlantic Division loses to the Metropolitan Division 10-6 in the semifinals in Los Angeles.
Video: MET@ATL: Karlsson buries nifty one-timer
June 14, 2017: Karlsson has surgery to repair torn tendons in his left foot. It's revealed that the injury occurred during the playoffs, in which Karlsson does not miss a game and has 18 points (two goals, 16 assists) in 19 games to help the Senators advance to within one game of the Stanley Cup Final.
Nov. 30, 2017: Speaking about his contract, which runs through the 2018-19 season, Karlsson tells the Ottawa Citizen, "When I go to market, I'm going to get what I'm worth, and it's going to be no less, no matter where I'm going."
"We're in a fairly similar boat, and again, when it comes down to it, I'm sure we're going to have discussions about what we're thinking and what we're going to do," Karlsson says of Los Angeles Kings defenseman Drew Doughty, who also can become an unrestricted free agent after the 2018-19 season. "It's a business that we're in and we (need to) get treated like we're a business, and we're going to treat everybody else like it's a business too."
Jan. 28, 2018: Karlsson has three assists for the Atlantic Division in a 7-4 win against the Metropolitan in the semifinals at the All-Star Game at Tampa Bay. He has no points in a 5-2 loss to the Pacific Division in the final game.
Feb. 26. 2018: After Karlsson remains in Ottawa following the 2018 NHL Trade Deadline, Senators general manager Pierre Dorion says the team will offer Karlsson a contract extension July 1, the first day they are allowed to do so. "I think Erik wants to be a Senator for life," Dorion says. "I don't want to speak for him, I'll let him speak for himself. We'll see what the next few months bring, but if Erik Karlsson is here on July 1, we will be making him a contract offer."
Feb. 27, 2018: One day after not being traded, Karlsson gets point No. 500 of his NHL career with a goal in the third period of a 3-2 loss to the Capitals.
Video: OTT@WSH: Karlsson nets 500th point from sharp angle
"I love this city, I love this community, I love everything about it," Karlsson says prior to the game. "I've been here for a long time. I've made Ottawa my home and it's always going to be my home. When that time comes I hope there's a place for me in the future and this team is going in the direction that I would like for us to have a chance in the near future."
April 2, 2018: In what ends up being his final game with the Senators, Karlsson has three assists in a 6-5 loss to the Winnipeg Jets at Canadian Tire Centre. When the game ends, he grabs the puck from the ice.
Video: WPG@OTT: Karlsson grabs puck at end of last home game
July 1, 2018: Dorion says the Senators have offered Karlsson an extension, but doesn't go into detail about the terms, saying, "I think we owe it to our fans and we made a promise at the town hall that we would make a contract offer to Erik Karlsson and we've done so"
Sept. 13, 2018: Karlsson is traded to the Sharks along with forward Francis Perron for forward Chris Tierney, defenseman Dylan DeMelo, forward Rudolfs Balcers, the rights to unsigned draft choice forward Joshua Norris, San Jose's first-round draft pick in the 2019 or 2020 NHL Draft, a second-round pick in the 2019 NHL Draft (the better of San Jose's own or Florida's own, previously acquired), a conditional pick in the 2021 NHL Draft (San Jose's own first- or second-round pick) and a conditional pick in the 2022 NHL Draft (San Jose's own first-round pick).