Boston traded Andrew Alberts to Philadelphia on Monday. ((Dave Sandford/Getty Images))

The Philadelphia Flyers bolstered their defence by acquiring blue-liner Andrew Alberts in a trade with the Boston Bruins Monday.

In exchange for Alberts, the Bruins received forward Ned Lukacevic and a fourth round pick in the 2009 NHL draft.

The 2009 draft selection will be upgraded to a third round pick if the Flyers re-sign Alberts at the end of his contract, which expires on June 30, 2009.

"Andrew is a big, competitive defenceman and he skates well," said Flyers general manager Paul Holmgren. "He will bring experience and depth to our team."

Alberts played in 181 games for the Bruins during his three-plus years with the club, tallying 19 points and 231 penalty minutes. 

He became expendable after the recent emergence of prospect defenceman Matt Hunwick, Boston's sixth round selection in the 2004 draft. Last season, the Michigan native played 13 games with the Bruins, recording one assist.

The trade also frees up some salary cap for the Bruins, as Alberts will earn $1.4 million US this season.

Drafted by the Bruins out of Boston College, Alberts was a sixth round pick (179th overall) in the 2001 NHL entry draft.

Lukacevic, 22, played 61 games for the Reading Royals of the East Coast Hockey League.

Originally drafted in 2004 by the Los Angeles Kings, Lukacevic has yet to play a game in the NHL.