The Boston Bruins traded Linus Ullmark to the Ottawa Senators, breaking up the NHL’s best goaltending tandem.

Ullmark, 30, was sent to the Senators for forward Mark Kastelic, goaltender Joonas Korpisalo and a 2024 first-round draft pick (25th overall). Ottawa will retain 25% of Korpisalo’s salary.

Ullmark has one more year left on this contract at a $5 million cap hit. He has a partial no-trade clause.

The Bruins were blessed with a goaltending tandem of Ullmark and Jeremy Swayman that was the foundation for their stellar team defense. They duo won the Jennings Trophy for the fewest goals allowed in 2022-23, the same season that Ullmark won the Vezina Trophy as the league’s top goaltender.

But this season saw Swayman earn slightly more games in the regular season and the majority of the starts in Boston’s postseason run that ended in the second round. Swayman is a restricted free agent and is expected to earn a long-term, big money deal with the Bruins. Considering the team’s other needs, trading Ullmark and his salary made sense from a financial standpoint.

Ullmark was 22-10-7 with a .915 save percentage and a 2.57 goals-against average.

Korpisalo has four years left on a 5-year contract he signed as a free agent last summer with the Senators. The salary retention means that the Bruins get him at a $3 million cap hit. Korpisalo, who also had a limited no-trade clause, was a major disappointment for the Senators last season with an .890 save percentage and a 3.27 goals-against average in 55 games.

They rid themselves of that contract and bring on one of the NHL’s top netminders to join a new tandem with goalie Anton Forsberg, who is signed through next season.

Kastelic, 25, appeared in 63 games during the 2023-24 season, recording five points and five assists for 10 points. He’s a 6-foot-4 center drafted in the 5th round in the 2019 NHL Draft who ranked third on the Senators in penalty minutes (63) last season. He’s entering his fourth NHL season.