ST. PAUL, Minn. — 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.

As with Seidenberg, there’s no timetable yet on McQuaid’s return.

Pass the torch

The Bruins’ second line of Patrice Bergeron, Brad Marchand and Reilly Smith has been helping each other all season.

When Marchand was struggling early through the worst stretch of his NHL career and Bergeron was getting up to speed after all the injuries he battled in the 2013 playoffs, Smith carried the scoring load. Then it was Marchand’s turn after he snapped out of the funk. And now Bergeron is taking his bow. His first-period goal in last night’s 4-3 shootout loss to the Wild gave him 10 in 11 games.

“It’s the way it goes sometimes,” Bergeron said. “Obviously, when you’re scoring, your linemates are doing lots of the work to get that puck to you, to create some openings to give you the puck. . . . It’s been great to play with these guys, and I think we’ve been establishing chemistry.”

Bergeron and Marchand have established resumes, but Smith is a different story. The winger, who was part of the Tyler Seguin trade, was great early this season but has cooled off, scoring just one goal in his previous 26 games entering last night.

Smith, like Bergeron, scored in the first period against the Wild, giving him 20 for the season, and he also seemed to have a little more jump in his step Saturday against the Flyers. The Bruins will need him to produce in the playoffs.

“I think he’s been getting back to playing his game, more than just the last game but the last few games,” Bergeron said. “It’s one of those things that as a player in his first full year, it’s something that younger guys go through during the year, they have ups and downs. But I think he’s been handling it really well and he’s been getting better.”

Claude Julien is seeing progress in Smith.

“He’s coming around,” the coach said. “I’ve felt it for a little over a week. I think he’s turning the corner.”

Eriksson elevates

With Jarome Iginla missing his third game out of the past four with a lower-body injury, Loui Eriksson got another chance to play on the top line. David Krejci was a healthy scratch, so Eriksson skated with Milan Lucic and Carl Soderberg. He had a career-high four assists while playing on the top line Saturday.

“It’s a fun opportunity,” Eriksson said. “I thought we did some good stuff in the last game, and even the game before, I thought we had some good chances.”

This has not been an ideal first season with the Bruins for Eriksson. After starting slowly, he missed 20 games with two separate concussions. But with the playoffs coming up, he has a chance to wipe out those bad memories.

“That’s why I wanted to come here, too, to make it to the playoffs,” he said. “We have a really good team and we’ve been playing really well. I’m really excited to start the playoffs.” . . .

Defenseman Kevan Miller missed his second straight game with an undisclosed injury that, like Iginla’s, is believed to be minor. . . .

Dougie Hamilton needed five stitches to close the gash he suffered from Phil Kessel’s high stick last Thursday. He also has a colorful shiner.