Seidenberg played with Adler Mannheim in Germany prior to coming to North America. A sixth-round pick by the Philadelphia Flyers (No. 172) in the 2001 NHL Draft, Seidenberg helped their American Hockey League affiliate, also located in Philadelphia, win the Calder Cup in 2005.

Seidenberg made his NHL debut on Oct. 10, 2002, with the Flyers at the Edmonton Oilers and scored his first NHL goal on Oct. 31, 2002, against the Phoenix Coyotes in Philadelphia. He had 11 points (one goal, 10 assists) in 25 playoff games for the Boston Bruins in 2011, helping them win the Stanley Cup.

Seidenberg, who is from Schwenningen, Germany, has represented his country in the Olympics, World Championship, the World Cup, the World Junior Championship and World Under-18 Championship. He played for Team Europe at the 2016 World Cup of Hockey and signed with the New York Islanders after the tournament.

Seidenberg's younger brother, Yannic, plays professional hockey in Germany.

NOTES & TRANSACTIONS

• Traded to Phoenix by Philadelphia with Philadelphia's 4th round pick (later traded to NY Islanders - NY Islanders selected Tomas Marcinko) in 2006 NHL Draft for Petr Nedved and Phoenix's 4th round pick (Joonas Lehtivuori) in 2006 NHL Draft, January 20, 2006.
• Traded to Carolina by Phoenix for Kevyn Adams, January 8, 2007.
• Signed as a free agent by Florida, September 14, 2009.
• Traded to Boston by Florida with Matt Bartkowski for Byron Bitz, Craig Weller and Tampa Bay's 2nd round pick (previously acquired, Florida selected Alexander Petrovic) in 2010 NHL Draft, March 3, 2010.
• Signed as a free agent by Mannheim (Germany), September 21, 2012.
• Signed as a free agent by NY Islanders, September 28, 2016.