Thomas chose to take this season off following the NHL lockout and was suspended by the Bruins after he didn’t report to training camp last month. The 38-year-old goalie is in the final season of a four-year deal that counts for $5 million against the salary cap.

The Islanders have plenty of room to fit Thomas’ salary on their cap, and this deal provides financial flexibility for the Bruins. Boston was up against the upper salary limit of $70.2 million, with Thomas’ salary factored in, and New York is only marginally above the minimum payroll of $44 million.

“We felt this would give us flexibility immediately. It was us being proactive,” Bruins general manager Peter Chiarelli said on a conference call. “I’ve had discussions on and off with the Islanders regarding this for a while. I don’t really want to get into details. I think I’ve made it known publicly this was something we would like to try to do at some point.”

NHL teams must be in full compliance of the salary cap by Friday, the 20th day of the league season. The Islanders will be even further above the cap floor with the imminent return of defenseman Lubomir Visnovsky, who reported to the club for the first time on Wednesday and then passed a physical on Thursday, which led to New York lifting its suspension and placing him on the active roster.

“We have acquired an asset for our organization,” Islanders general manager Garth Snow said of Thomas. “This acquisition allows us flexibility with our roster moving forward.”

Thomas is unlikely to play for the Islanders this season or in the future. New York already has veteran goalies Evgeni Nabokov and Rick DiPietro on its active roster.

Thomas’ absence has created an opportunity for Tuukka Rask to lead the talented Bruins in net, and he’s delivered. Rask is 6-1-1 with a 1.97 goals-against average for Boston, the top team in the Eastern Conference as play began on Thursday.

“Without getting into specifics,” Chiarelli said, “the (draft pick) condition is basically if (Thomas) plays.”

Thomas, a two-time Vezina Trophy winner as the NHL’s top goalie, has played in 378 regular-season games — all with the Bruins. He has gone 196-121-45 with a 2.48 GAA and 31 shutouts. Thomas ranks fourth on Boston’s career wins list and third in shutouts,

He also has a 29-21 mark in the postseason with a 2.07 GAA and six shutouts. Thomas won the Vezina and Conn Smythe Trophy as playoff MVP when the Bruins won the Stanley Cup in 2011.

“He had a very good career here,” Chiarelli said. “I can’t say enough of his contributions to the team. The journey he took us on in the Stanley Cup was amazing. I was happy to be along for the ride.

“Nothing would suggest to me he’s coming back this season.”

Visnovsky was traded to the Islanders by Anaheim last June, and the defenseman filed a grievance to have the deal voided because he claimed a no-trade clause in his original contract with Los Angeles was valid. An arbitrator ruled against him.

Visnovsky left his hometown team in the KHL and joined the Islanders. He wasn’t in the lineup Thursday against the Rangers.

Chiarelli wouldn’t say if Thomas could ever return to the Bruins, but didn’t give any indication that it was likely to happen.

“I don’t want to speculate on that,” he said. “Tim can be a character and he can also be principled in a lot of different things. He is/was a heck of a goaltender. I liken him sometimes to that left-handed pitcher that’s a little quirky but wins a lot of games and throws 200 innings a year.

“I don’t know how it would have played out.”