For Stanley Cup hopefuls, the NHL trade deadline is a day to make one last push to build a roster strong enough to capture the chalice, while for others, it may be the first day of a potentially painful rebuild.

Over the past handful of years, the deadline has seen deals that nearly cemented championships before the playoffs began - and other moves that not only crippled teams' chances of success at the time, but derailed potential future glory.

Here are the five biggest deadline-day trades since 2010:

Martin St. Louis to the New York Rangers

On March 5, 2014 the Tampa Bay Lightning dealt team captain and leading scorer Martin St. Louis to the New York Rangers for forward Ryan Callahan, a conditional pick in the 2014 draft, and the team's first-round pick in 2015.

Beyond the significance of the player, what made the trade so monumental was the building tension between St. Louis and general manager Steve Yzerman that preceded it.

Though it became known that St. Louis had requested a trade to the Rangers earlier in his career in order to be closer to his family, St. Louis was believed to hold a grudge about being the final player cut from Team Canada's 2014 Olympics roster by his very own GM, which didn't bode well.

St. Louis was ultimately added to that squad thanks to a Steven Stamkos injury, but the damage was done, and soon after, his ticket to the Big Apple was punched.

Filip Forsberg to the Nashville Predators

While this trade did little to aid either team for its playoff push, it had drastic implications later.

On April 3, 2013, the Washington Capitals traded 2012 first-round pick Filip Forsberg to the Nashville Predators for forwards Martin Erat and Michael Latta.

The move was a complete head-scratcher: Why did the Capitals give up on a budding prospect so early for a question mark in Erat?

Erat failed miserably in his tenure with his new club, putting up just one goal and three points in the final nine games of the 2013 season and going pointless in the postseason.

He managed just one goal in 53 games with the Capitals the following season before being shipped to the then-Phoenix Coyotes. He's now playing in the KHL.

Meanwhile, in his first taste of the NHL last year, Forsberg impressed by tallying 26 goals and 63 points - marks Erat never hit in 12 full seasons in the league.

Marian Gaborik to the Columbus Blue Jackets

Marian Gaborik has become one of the more talked-about bodies at recent trade deadlines.

In 2013, the Rangers traded Gaborik (and defensemen Blake Parlett and Steven Delisle) to the Columbus Blue Jackets for Derek Dorsett, Derick Brassard, John Moore, and a 2014 sixth-round pick.

It was interesting to see the Rangers deal Gaborik - who'd tallied 41 goals just one season earlier - as the team was heading into the playoffs.

The trade appeared to work out for the Rangers, though: Brassard went on to lead the team in scoring in the postseason, totaling 12 points in 12 games, and remains a key piece of the club's roster to this day. The move also set up Gaborik for success later - but not with Columbus.

Ben Bishop to the Tampa Bay Lightning

The 2013 trade deadline was a fun day.

The Lightning and Ottawa Senators got in on the action as the Senators shipped goaltender Ben Bishop to the Lightning for forward Cory Conacher and a fourth-round pick in 2013, previously acquired by the Philadelphia Flyers.

After setting the American Hockey League on fire, Conacher burst onto the scene in Tampa, potting nine goals and 24 points in his first 35 games. The Lightning appeared to know his capabilities and sold him at his highest value, acquiring their potential franchise goaltender in the process.

Conacher has since been traded twice more and is now producing effectively in the Swiss Elite League, making it fairly easy to name a winner in this transaction.

Bishop, meanwhile, has amassed 104 wins as a member of the Lightning and helped the team reach the Stanley Cup Final last season, falling just two wins shy of hockey's ultimate prize.

Marian Gaborik to the Los Angeles Kings

After the 34-year-old was shipped out to aid a club in 2013, one year later, Gaborik was the key piece in a move to construct a Stanley Cup champion.

Gaborik was acquired by the Los Angeles Kings in exchange for forward Matt Frattin, the Edmonton Oilers' third-round pick in 2014, and the Toronto Maple Leafs' second-round pick in 2015.

The deal paid immediate dividends for the Kings as Gaborik was reborn on the West Coast, putting up five goals and 16 points in 19 games to conclude the regular season.

However, he truly demonstrated his value during the playoffs when he went off for 14 goals and 22 points in 26 games, making a large contribution to the Kings' second Stanley Cup in three seasons.

-With h/t to Today's Slapshot