The preseason is not even a week old, and the Bruins are already getting hit by the injury bug.

On a day of significant developments on Thursday, GM Don Sweeney announced a trio of Bruins suffering injuries during the first two preseason games, as well as a pair of roster cuts. One injury, in particular, will hit the Bruins blueline hard.

Torey Krug, who left Tuesday’s 4-2 win over the Red Wings after taking a puck to the jaw, will miss at least the first few games of the regular season. The former Michigan State Spartan will be reevaluated in three weeks. Jakob Forsbacka Karlsson, who also left Tuesday’s game with an upper-body injury, is day to day, as is Matt Beleskey, who suffered a foot contusion against the Canadiens.

On top of the injury news, the Bruins announced a pair of roster cuts. Both forward Jack Studnicka and goaltender Kyle Keyser will return to the Oshawa Generals for the 2017-18 season.

Krug’s injury opens up another spot on the Bruins’ blueline for the time being. Notable candidates who could seize the opportunity include Matt Grzeclyk, Rob O’Gara, Paul Postma, Jeremy Lauzon and Jakub Zboril.

Postma and Grzeclyk are included in tonight’s lineup against the Flyers (which will be broadcasted on NESN and NHL Network), along with the preseason debuts of Zdeno Chara, Patrice Bergeron, Brad Marchand and Tuukka Rask.

Here are tonight’s forward and D pairings.

Morning skate lines:

Marchand – Bergeron – Bjork
Agostino – Spooner – Heinen
Gabrielle – Nash – Acciari
Blidh – Cave – Senyshyn
Koppanen

— Boston Bruins (@NHLBruins) September 21, 2017

Morning D-pairs:

Chara – Carlo
Grzelcyk – Cross
Lauzon – Postma

Goalies: Rask, Subban

— Boston Bruins (@NHLBruins) September 21, 2017