OTTAWA — The Ottawa Senators promised they were going into rebuild mode earlier this week.

They weren't kidding. 

Ending months of speculation and creating yet another juicy headline, the Senators traded their franchise player — captain Erik Karlsson —to the San Jose Sharks on Thursday.

In the end, the defenceman and the Senators did not see eye to eye — with the deal being done on the eve of the first on-ice session at training camp.

"I don't think I could have ever prepared for this, that's why I don't have anything written and I still haven't wrapped my mind around what is going on," said an emotional Karlsson. "As you said, there's been a lot of noise for almost a year now, but I never in my wildest imagination thought that I was going to leave this place."

The Senators dealt Karlsson and prospect forward Francis Perron to the Sharks. Ottawa gets forwards Chris Tierney and Rudolfs Balcers, defenceman Dylan DeMelo, prospect forward Josh Norris and two conditional draft picks. If San Jose re-signs Karlsson, Ottawa receives a conditional 2021 second-round selection — or a first-round pick (not lottery protected) if the Sharks reach the Stanley Cup final in 2019.

Ottawa receives San Jose's first-round choice in either 2019 or 2020 (not lottery protected). If the Sharks miss the playoffs in 2018-19, it will be a 2019 selection, otherwise it will be in 2020. Ottawa gets a second-round choice in the 2019 draft from San Jose (which will be the higher of the two picks the Sharks currently own — the Florida Panthers' and their own).

The deal is sure to be a defining moment for a team that has had all kinds of problems on and off the ice in recent months.

The Senators took the unusual step of releasing a video late Monday night with defenceman Mark Borowiecki interviewing owner Eugene Melnyk, who made it clear the team was ready to rebuild. Many interpreted it as a sign that Karlsson's days in Ottawa were numbered.

"This is the right moment for us to rebuild our team," said Senators general manager Pierre Dorion. "Shape our future with all these core pieces while adding a faster, younger and more competitive team on the ice. This trade represents the best opportunity for the Ottawa Senators to rebuild towards a consistent excellence that we are striving for."

Dorion admitted the decision to rebuild was made in February, yet during town hall meetings with fans in April said, "at the end of the day it will be (Karlsson's) choice. If we offer him a fair contract and he doesn't want to sign here, then we will have to look at other options. The ball will be in his court.”

Karlsson, whose contract expires at the end of this season, doesn't quite see it that way.

"I think they made it very clear in what direction they were going with and unfortunately I wasn't part of that and I respect that it's their decision," he said. "I was not part of that plan and that's why we're standing here today. From my point of view, that's sad. I never wanted to leave this place, but at the same time I respect their decision."

The Senators, who did offer Karlsson an extension over the summer, believed this was the best option.

"You get to a certain point and it's probably best for all parties to move on," said Dorion. "For the benefit of the organization, for the benefit of the rebuild, for the succession of the rebuild, I think today we made the proper decision."

Selling that to the fans may be difficult, though. There were thousands of empty seats for some games last season, and the organization figures to face a similar challenge in 2018-19. 

Karlsson is a two-time Norris Trophy winner and led or tied the Senators in scoring the past five years.

The six-foot, 191-pound Swede was selected by the Senators with the 15th overall pick in the 2008 NHL Entry Draft.

Karlsson's breakout season came in 2011-12 when he had 78 points (19 goals, 59 assists), while averaging 25:19 of ice time, but his performance in the 2017 playoffs stands out.

The dynamic captain led the Senators in scoring with 18 points in 19 contests as Ottawa advanced to Game 7 of the Eastern Conference final before losing to the Pittsburgh Penguins in double overtime. He averaged more than 28 minutes of ice time despite having torn tendons in his left foot, which required off-season surgery.

Karlsson, who took over as captain in 2014, says he will continue to give back to the city he now calls his "forever home."

"It's a city that I'm going to set my roots in and forever stay in, even though I'm not going to represent this hockey club anymore,” said Karlsson. "It's always going to be my home and it's always going to be a community that I'm going to be as much involved in as I possibly can and give back in whatever way that I can.”

The departure of the 28-year-old is the latest development in what has been a turbulent stretch for the Senators.

Things started to go sideways last fall after the club returned from a two-game sweep of the Colorado Avalanche in Sweden, going an ugly 1-9-3 over its next 13 to begin a tumble down the standings

Then on the eve of franchise's showcase outdoor game in mid-December, Melnyk rained on his own parade by musing to reporters at a media availability on Parliament Hill that he might move the team if ticket sales didn't improve.

That launched the #MelnykOut hashtag on Twitter the same month, and while Melnyk eventually backtracked on the relocation talk, some fans decided to vent their frustration by raising money to fund a series of billboards featuring the slogan.

Through it all, Karlsson's future remained a key talking point ahead of February's trade deadline.

He ended up staying put, but tragedy struck in March when Karlsson and his wife Melinda announced their first child, a son they named Axel, was stillborn.

More controversy bubbled to the surface in May when former captain and franchise icon Daniel Alfredsson, who left his role with Ottawa as a senior adviser the previous summer, was quoted saying he hopes the team gets a new owner.

Then assistant general manager Randy Lee was charged with harassing a 19-year-old male hotel shuttle driver in Buffalo, N.Y., during the NHL's pre-draft scouting combine. He was suspended by the team two weeks after being charged.

And if that wasn't enough, news broke in June that Karlsson's wife had filed a peace bond against Monika Caryk, the fiancee of former teammate Mike Hoffman, for alleged cyberbullying.

Hoffman, who was traded a week later, and Caryk have denied the allegations. A civil suit is ongoing.

Lee, who was also GM of the Senators' AHL affiliate, resigned from both jobs with the organization last month.

Lisa Wallace, The Canadian Press