A day before free agency begins in the NHL, the Boston Bruins cut ties with one of their top defensemen Thursday.

The Bruins placed Dennis Seidenberg on buyout waivers. Seidenberg had two years left on his contract at a salary-cap hit of $4 million. The buyout saves the Bruins $2.83 million next season.

“It’s a shock,” Seidenberg told the Boston Herald. “(General Manager) Donnie (Sweeney) called me (Thursday morning) and he said it was a tough call to make but he had to buy me out, that they were going with the kids. Told me I was a great guy and that was it.”

Seidenberg, who helped the Bruins win the Stanley Cup championship in 2011, said he cherished his time in Boston.

“I loved playing there, I loved living in the city. I’m going to miss it,” he said.

There had been speculation that Seidenberg could be a target of a buyout, but with the buyout period coming to an end at 5 p.m. Thursday, he thought he might be safe.

Sweeney reportedly has been trying to acquire another top-four defenseman on the trade market. If that continues to fail, he’ll go into the unrestricted free-agent market Friday.

But it sounds like Colin Miller and Joe Morrow, and perhaps even first-year pros like Brandon Carlo and Matt Grzelcyk, will get an opportunity to play regardless of what acquisition is made.

On Thursday, Boston signed Torey Krug to a four-year contract worth $21 million, giving the team four NHL defensemen – Krug, Zdeno Chara, Adam McQuaid, and Kevan Miller – under contract, with deals to be worked out for Morrow and Colin Miller.

Seidenberg will be an unrestricted free agent, but with the timing of the buyout he didn’t get to benefit from the open interview period.

“That would have been nice but oh well. I guess I’ll just go into free agency (Friday) and go from there,” said Seidenberg, who will turn 35 on July 18.

In his prime, Seidenberg teamed with Chara as a great lockdown defensive pair, especially during the Bruins’ run to the Stanley Cup in 2011.

But after signing a four-year, $16 million extension prior to the 2013-14 season, he was beset by injuries.

In the middle of that first season of the extension, he suffered two knee ligament tears and was done for the season. He played the entire next season, but his play was not at the same high level it had been before he was hurt.