BOSTON - Dennis Seidenberg has worn the colors of four teams in the five-plus years since the Flyers cut their ties with him in a deal with the Phoenix Coyotes for an over-the-hill Petr Nedved midway through the 2005-06 season.

Now that he has found a home with the Boston Bruins, the defenseman is treating the team that drafted him like an uninvited guest.

If the 29-year-old Seidenberg hasn't been the best defenseman in the Eastern Conference semifinal series, which the Bruins can end in a sweep on Friday at TD Garden, he's second only to his partner along the blue line - 6-foot-9 Zdeno Chara.

Seidenberg's numbers in the Bruins' three wins over the Flyers are somewhat staggering. He is plus-9 with three assists. He has been on the ice for 11 of Boston's 15 goals. He has blocked 12 shots and squeezed off 10. In the Bruins' 3-2 overtime win in Game 2, Seidenberg was on the ice for a game-high 36 minutes, 26 seconds, leading the team with six blocks. After that game, Boston coach Claude Julien called Seidenberg a horse.

"He doesn't get tired," he said. "He can take it."

Seidenberg also has helped make life a bit easier for goalie Tim Thomas by adeptly sweeping rebounds from harm's way.

"What he's given us is what we knew he could do for us," Julien said Thursday. "He's a player who has played extremely well in big games. And when he's at his best and he's very confident, he's an elite defenseman."

Even though it's been nine years since the Flyers signed Seidenberg to his first NHL contract, he'd been in only 19 playoff games before this season. A year ago, when the Flyers came back to beat the Bruins after losing the first three games in the conference semifinals, Seidenberg watched from the press box, after a skate blade had sliced a tendon in his left forearm with four games remaining in the regular season.

"It's nerve-racking [to watch], and it's not fun," Seidenberg said. "It's more gratifying being part of the team this year and being able to help out."

With Seidenberg healthy, Julien knows the Bruins are better equipped to deal with the Flyers this time around.

"When you look at the way he's performed, you can see how much we missed him last year in the playoffs and how much better we would have been as a team with him on it," Julien said. "He's been like an unsung hero to many, but it certainly hasn't eluded our view of him."

Seidenberg's time with the Flyers was marked by injuries and frustration. His major setback while with the Flyers occurred in January 2004, when defenseman Markus Ragnarsson fell on him during a one-on-one drill and broke Seidenberg's leg.

Seidenberg played 58 games for the Flyers after he was called up from the Phantoms in 2002-03, but only 34 more before he was traded for Nedved.

Seidenberg was a free agent before the 2009-10 season and he hoped to reach an agreement for a return to the Flyers, but the team told him it couldn't fit him under the salary cap, so he signed for one year and $2.5 million with the Florida Panthers.

Finally, the German-born Seidenberg has stability in his career. He's in the first season of a four-year deal with the Bruins, and he's on their top defensive pairing, averaging more than 28 minutes a game in the postseason. The Bruins acquired him from the Panthers at the 2010 trade deadline, hoping he would help them finally get into the conference finals for the first time since 1992. A year later, he's giving them what they had hoped for.