Junior/Collegiate

Prior to joining the NHL, Leopold played for the Armstrong Falcons^[1] of Plymouth, Minnesota, and went on to play collegiate hockey with the University of Minnesota from 1998 until 2002, where he helped the Golden Gophers win an NCAA national championship despite pressure to leave the University early to play in the NHL. After his first year with Minnesota, scoring 23 points, Leopold was drafted in the 1999 NHL Entry Draft in the second round, 44th overall, by the Mighty Ducks of Anaheim as a prospective offensive defenseman. After completing his sophomore season with the Golden Gophers, Leopold became the property of the Calgary Flames, traded by the Mighty Ducks in exchange for Andrei Nazarov and a second-round draft pick.^[2] In 2001–02, his final season with the University of Minnesota, he won the Hobey Baker Award for being the season's outstanding player in college hockey.^[3] He also played for the US in the World Championships that year.

Professional

Leopold started his professional career in the NHL in 2002. He played 58 games for the Calgary Flames and scored four goals and 14 points. In his second season, Leopold would play in all 82 regular season games, scoring 33 points as well as contributing to the Flames' playoff run to the 2004 Stanley Cup Finals, play which earned him a spot in the defense of the American national team for the 2005 World Championships as well as for the 2006 Winter Olympics.

After one more season with the Flames, Leopold was traded to the Colorado Avalanche at the 2006 NHL Entry Draft.^[4] Leopold's first season with the Avalanche, in 2006–07, was all but wiped out due to injury. Having missed the first 25 games of the season recovering from hernia surgery,^[5] he then suffered a groin injury on December 11, 2006, ruling him out for another 17 games.^[6] Just a month later, Leopold was injured again, fracturing his wrist on February 17, 2007, effectively missing the rest of the season, and playing in just 15 games.^[7] At season's end, Leopold was re-signed by the Avalanche to a two-year contract on May 22, 2007.^[8]

In the 2007–08 season, Leopold was again struck down by another injury-plagued season. Throughout the course of the season, he missed 35 games with a hip ailment, lacerated leg and pneumonia.^[9] He also suffered a concussion when he was hit high by Steve Ott on March 9, 2008.^[10] Ott was subsequently suspended for three games.

Leopold recovered to full health in time for the 2008–09 season. He played in every game with the Avalanche until the NHL trade deadline, when he was traded back to the Calgary Flames for Lawrence Nycholat, prospect Ryan Wilson and a second-round draft pick.^[11] Leopold then played all 19 games for the Flames, becoming the first Flames player to play 83 games of an 82-game season,^[12] a feat that Ian White would repeat in 2010.^[13]

On June 27, 2009, as an impending free agent, Leopold's negotiation rights were traded by the Flames to the Florida Panthers, for the negotiation rights of Jay Bouwmeester, at the 2009 NHL Entry Draft.^[14] After testing free-agency, Leopold signed a one-year contract with the Panthers on July 2, 2009.^[15]

In the 2009–10 season, Leopold scored seven goals and 18 points in 61 games with the Panthers. On March 1, 2010, he was then traded to the Pittsburgh Penguins for a second-round draft pick in the 2010 NHL Entry Draft.^[16] On April 16, 2010, in Game 2 of a playoff series between the Penguins and the Ottawa Senators, Leopold's series was ended by a devastating hit from Senators defenseman Andy Sutton. Leopold, who had a history of concussion injuries, remained unconscious on the ice for several minutes.^[17] Leopold later returned to the Pens' lineup for Game 2 of the Eastern Conference Semi-final matchup against the Montreal Canadiens.

On July 1, 2010, Leopold left the Penguins as a free agent and signed a three-year contract with the Buffalo Sabres.^[18]

In the final year of his contract with the Sabres, during the lockout-shortened 2012–13 season, he was traded to the St. Louis Blues in exchange for a second-round pick and a conditional fifth-round pick in the 2013 NHL Entry Draft on March 30, 2013.^[19]

In the 2014–15 season, with limited playing time in St. Louis, on November 15, 2014, Leopold was traded from the Blues to the Columbus Blue Jackets in exchange for a fifth-round draft pick in 2016.^[20] Leopold played 18 games with the Blue Jackets, registering one goal and two assists, before he joined his third team in the year when he was dealt to the Minnesota Wild in exchange for Justin Falk and a fifth-round pick in 2015 on March 2, 2015.^[21]

Regular season and playoffs

International