The hopes of Dennis Seidenberg returning to the Bruins some time this season remain slim, but he took a significant step yesterday. According to a source, the defenseman skated at Ristuccia Arena for the first time since undergoing knee surgery.

It’s believed he skated for about 15 minutes, and it’s not known just how well his knee held up, but it is a noteworthy milestone in his rehabilitation.

Seidenberg seemingly was lost for the season when he suffered a torn ACL and MCL late in a game against Ottawa on Dec. 27, when he got tangled up with the Senators’ Cory Conacher.

The loss of Seidenberg was a tough blow for the B’s, but they have done well to fill his void. Using primarily Matt Bartkowski and newcomer Andrej Meszaros — acquired at the trade deadline — in Seidenberg’s spot on the left side of the second defensive pairing, the B’s have maintained their team defense concept. Going into last night’s game against the Wild, the B’s were ranked second behind only the Los Angeles Kings in goals-against average (2.09).

The Bruins likely will have to make a deep playoff run to give Seidenberg a chance to return. And if he becomes healthy enough to play, it might take an injury to one of the current defensemen to get him back in the lineup considering how long he’s been on the shelf. . . .

Defenseman Adam McQuaid also skated in Wilmington. McQuaid has not played since Jan. 19, when he suffered a relapse of a troublesome quad injury that had knocked him out of the lineup earlier in the season. He had not skated since having a setback in practice just after the Olympic break.