The Boston Bruins announced this morning that veteran defenseman Dennis Seidenberg will undergo surgery tomorrow to repair a herniated disc in his back.

While losing one of the team’s experienced defenders is another step backwards for the B’s, who traded Dougie Hamilton in the offseason, it means for the first two months of the season and perhaps longer, the club will be able to better determine if youngsters Colin Miller or Joe Morrow are ready for primetime.

Miller impressed in his first preseason game Sunday night, notching a pair of power play assists in Boston’s 2-0 win against New Jersey in Providence. He showed off the kind of mobility that Boston desperately needs, moving the puck accurately and using his lateral movement to open up lanes through the Devils’ PK.

Morrow was not as productive last night in the B’s 2-1 OT win over Washington at home, but played a strong game from the back end as well. He’s always been a fine skater and puck mover going back to his WHL days at Portland, but in 15-game audition in Boston last season, Morrow seemed to play more inside of a defensive shell. If the B’s can unshackle him and let him accept a little more risk by doing what he does best- taking the puck and going with it- the team might be able to address the capability gaps opened up with Hamilton’s departure.

Seidenberg out of the lineup means the team does not have to make tougher choices based on who has to go on waivers (Trotman, Morrow, Kevan Miller) and who doesn’t (Colin Miller). If worried about losing a player on the waiver wire, the B’s can now hold onto the players and carry them without the hand being forced. They will have to allocate the cap hit associated with every player on the roster, however- and that’s something to keep an eye on.

We wish Seidenberg well in a speedy recovery, but as of today- Boston’s opening night defense depth chart might look a bit like this (should the Bruins opt to carry 8 defenders as Claude Julien hinted at this week):

Zdeno Chara

Torey Krug

Zach Trotman

Adam McQuaid

Matt Irwin

Colin Miller

Joe Morrow

Kevan Miller