The Sharks then pounced and signed Karlsson to a $92 million, eight-year deal on Monday, turning a one-year rental into a long-term commitment to one of the league's most dynamic defensemen.
"This was a big decision for me," Karlsson said. "Ultimately at the end of the day, I know it's the right one for me, my family and this organization as well. I'm very happy with how everything happened and that they didn't force me into making a decision earlier than this."
A person with knowledge of the deal said it carries an annual cap hit of $11.5 million and includes a full no-movement clause. The person spoke to The Associated Press on condition of anonymity because the team did not announce terms of the contract.
The Sharks acquired the two-time Norris Trophy winner just before the start of last season from Ottawa. Karlsson was hampered by groin injuries for much of his first season in San Jose but also showed flashes as he helped the Sharks reach the Western Conference final for the fifth time in the past 15 seasons, where they lost to eventual champion St. Louis in six games.
Karlsson wore down at the end of the series against the Blues. He missed most of the second half of the third period in a Game 4 loss to St. Louis, missed the entire third period when the Sharks lost the following game and then didn't travel for the Game 6 loss that ended San Jose's season. The 29-year-old Karlsson had surgery on the groin on May 31 and is expected to recover fully before the start of next season.
The Sharks were confident enough in his health to give him the richest contract of any defenseman, topping the $88 million, eight-year extension Drew Doughty signed in Los Angeles last summer. The only current deals worth more annually are Connor McDavid's $12.5 million cap hit on an eight-year deal in Edmonton and Auston Matthews' $11.6 million cap hit on a five-year contract in Toronto.
"We're extremely comfortable," general manager Doug Wilson said. "It's fixed. It will be 100% come September and he's putting in the work for that. That's one of the great advantages to having the knowledge you go through the process to make this decision. It would have been more difficult for us if we were on the outside and never knew the player and you have the unknown factors in this."
Karlsson got off to a slow start in San Jose following the trade and then was slowed by the groin injury that sidelined him for 27 of the final 33 regular-season games. He finished his first season with the Sharks with three goals and 42 assists in 53 games.
But during a stretch from December to January, Karlsson showed he still has the ability to be the best defenseman in the NHL. He had points in 15 straight games that he played and had 25 points total in that span.
Karlsson got hurt Jan. 16 in Arizona and never was completely healthy again. He still managed to make a major impact in the playoffs, when he had 14 assists in 19 games and scored two goals, including the overtime winner in Game 3 against the Blues.
Karlsson will be part of an elite, yet expensive, defense group for the long term in San Jose, alongside 2017 Norris Trophy winner Burns and shut-down defenseman Marc-Edouard Vlasic. All three are now under contract at least through the 2024-25 season and an annual cap hit of $26.5 million.
With top centers Logan Couture and Tomas Hertl also signed long term, the Sharks figure to remain a contender for the near future.
"We're going to have a great chance at winning the Cup not only next year but for a lot of years moving forward," Karlsson said. "That's always going to be our mindset. ... We had a great run this year but we didn't make it all the way. That's not what we set out to do."
San Jose still has two high-profile pending unrestricted free agents to try to sign. Captain Joe Pavelski is set to hit the market after scoring 38 goals this season. Thornton also is a free agent but hasn't announced whether he plans to retire or try to come back to San Jose for another season at age 40. Wilson said this deal doesn't preclude one with Pavelski and said there will always be a place for Thornton if he wants to return.
The Sharks will have to send their second-round pick in 2021 to Ottawa to complete the deal because they kept Karlsson.
AP Hockey Writer Stephen Whyno contributed to this report.
More AP NHL: https://apnews.com/NHL and https://twitter.com/AP_Sports
Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.