Weller was born in Calgary, Alberta. As a youth, he played in the 1995 Quebec International Pee-Wee Hockey Tournament with the Calgary Junior Flames minor ice hockey team. Weller was the St. Louis Blues 5th round choice, 167th overall, in the 2000 NHL Draft. After playing with the Charlotte Checkers of the ECHL and the Hartford Wolfpack of the American Hockey League, he was signed as a free agent by the Phoenix Coyotes on July 19, 2007. He scored his first career NHL goal on October 25, 2007, against the Anaheim Ducks; the goal turned out to be the game-winning goal. On July 1, 2008, Weller signed a two-year, $1.2 million contract with the Minnesota Wild. On October 18, 2009, he was traded to the Boston Bruins along with prospect Alexander Fallstrom and a second round draft pick in 2011 in exchange for Chuck Kobasew. On March 3, 2010, Weller was traded from the Bruins to the Florida Panthers along with Byron Bitz and a second round draft pick in exchange for Dennis Seidenberg and Matt Bartkowski. On 1 November 2010, the Cardiff Devils of the EIHL in the UK announced they had signed Weller, who was a free agent at the time. He became the most experienced NHL player after Theoren Fleury to play in the Elite League, playing in his preferred position as a defenceman. With Weller on board, the Devils embarked on 22-game unbeaten streak, breaking the league and world records. However, the Devils narrowly missed out on the league title, finishing level on points with the Sheffield Steelers but having won 1 regulation game less, before being beaten in the Playoff final 5–4 to the Nottingham Panthers. After his first season in the UK Weller quickly established himself as a reliable, solid two way defenceman, drawing admiration from across the league, culminating in 3 awards - League Player of the Season, Player of the Season and Defenceman of the Season. Weller left the Devils to join Villacher SV of the Austrian Hockey League for a single season before venturing to Germany to accept a try-out with ERC Ingolstadt for the 2012–13 season. In establishing a position within Panther's lineup, Weller was signed for the remainder of the campaign on September 5, 2012.
