The NHL awards the James Norris Trophy to the "defensive player who demonstrates throughout the season the greatest all-round ability in the position."
Nicklas Lidstrom of Detroit has won the Norris seven times, including last season, but it's unlikely he'll win it again this year. Lidstrom is having a good but not great season for the Red Wings.
This award almost always goes to an offensive-minded defenseman. The last true stay-at-home blueliner to win it was Rod Langway of the Washington Capitals back in 1984.
While Lidstrom, Florida's Bryan Campbell, Boston's Zdeno Chara and Winnipeg's Dustin Byfuglien will all get some consideration, there are three candidates who are likely to be finalists for the Norris Trophy this year.
Karlsson has really matured in his third NHL season and leads all defensemen in points and scoring by a large margin.
The 21-year-old Swede has been a major part of the Senators' surprise run towards a playoff spot. He's a power-play quarterback and has even added four game-winning goals.
The biggest question marks surrounding Karlsson are his mediocre play in his own zone and the fact that he is young and is first establishing himself as an elite defenseman in this league. Despite that, he should be the favorite to win the Norris this year.
Weber and Ryan Suter give the Nashville Predators a duo that is second to none in the league.
Weber is second among defensemen in goals and in the top five overall in points. He also plays very well in all three zones of the ice, which gives him an advantage over Karlsson. Weber is not afraid to block shots or play a physical game, making him a complete player.
He finished a close second to Lidstrom in last year's voting, and this may be the year he finally wins the Norris.
Edler plays for a consistent winner in the Vancouver Canucks and is one of the reasons they play strong team defense.
He contributes to both the power play and penalty kill and also plays a strong, physical defensive game without sacrificing point production.
Edler is presently fourth among defensemen in scoring and at 25 years old, he's just starting to enter the prime of his career.
The Norris Trophy remains the prized award for NHL blueliners. Who will take it home this year?