Trades happen in hockey. The NHL is a business. The Ottawa Senators and New York Rangers get that.

But for two particular players such generic phrases will not ease the pain of separation. For the first time, Derick Brassard and Mats Zuccarello will be on opposite sides in a playoff series. The NHL's greatest bromance will have to endure the most heated setting the sport has to offer.

Brassard and Zuccarello are both 29 -- they were born 21 days apart. Zuccarello, a Norweigian, played for the Rangers from 2010-2012 before heading to Russia for a year. He re-signed with the team late in the 2012-13 season. It was around this time that Brassard, a Canadian and the sixth overall pick by the Blue Jackets in 2006, was traded to the Rangers.

In 2013-14, their first full season together, Brass and Zuc helped lead the Rangers to a Stanley Cup Final appearance. The following season, the Rangers won the Presidents' Trophy and reached the Eastern Conference Finals. In 2015-16, they were the Rangers' top two scorers. Brassard and Zuccarello, with their fun-loving spirits on the ice, established themselves as fan favorites at Madison Square Garden, but the experience ended last July when Brassard was traded to Ottawa.

In their three and a half years as teammates, Brassard and Zuccarello kept their friendship documented on social media:



Great season even tho we wanted to win! Now back to norway and right to play charity game with carl hagelin! But gonna miss u @brassardderick xoxo A post shared by matszuccarello (@matszuccarello) on Jun 18, 2014 at 2:04pm PDT



I guess no one else wanted to see the ninja turtles tonite! @matszuccarello A post shared by Derick Brassard (@brassardderick) on Aug 19, 2014 at 5:27pm PDT

Before the 2014-15 season, Zuccarello actually flew not to New York, but to Ottawa (Brassard's hometown), to road trip to training camp with Brassard. Zuc started using the hashtag, #werethetwobestfriendsthatanyonecanhave to cover their lives.



Roadtrip baby!! Ottawa to nyc! #werethetwobestfriendsthatanyonecouldhave A post shared by matszuccarello (@matszuccarello) on Aug 18, 2014 at 11:42am PDT

And Brass and Zuc were always up for fun events with each other, whether it was going to the zoo with Carl Hagelin:



Bronx zoo with the amigos #16 #62 #36 A post shared by matszuccarello (@matszuccarello) on Nov 30, 2014 at 11:18am PST

Or going to the U.S. Open with Ryan McDonagh:



I got my first taste of the US open tonight!! @matszuccarello @rmcdonagh27 A post shared by Derick Brassard (@brassardderick) on Sep 9, 2015 at 6:59pm PDT

Or hanging by the beach:



resting up and getting some vitamin d during the break A post shared by Derick Brassard (@brassardderick) on Jan 26, 2016 at 2:06pm PST

Or playing some sort of weird pool tennis game with Kevin Hayes:



Last weekend of the summer☀️ 30 days until the fun starts @brassardderick @kphayes12 A post shared by matszuccarello (@matszuccarello) on Sep 7, 2015 at 8:32am PDT

Brassard and a few other Rangers even went to Norway to play in a charity game Zuccarello hosted:





Zucc also got Brass this amazing "All I want for Christmas is Zuuuuuc" sweater in 2015.



At least brass got what he wants for christmas merry chistmas and happy holidays everyone A post shared by matszuccarello (@matszuccarello) on Dec 24, 2015 at 2:16pm PST

They were the two best friends that anyone could have ...



4 more years of fun @matszuccarello ! Congrats A post shared by Derick Brassard (@brassardderick) on Mar 1, 2015 at 8:42pm PST





Until it all ended last July 18. Brassard and a 2018 seventh-round pick were traded to the Senators for Mika Zibanejad and a 2018 second-round pick. Just like that, the legend of Brass and Zucc was over.



Thank you for all the support this year rangerstown..looking forward to next season. Also congrats to this guy on his Masterton Trophy nomination . Well deserved A post shared by Derick Brassard (@brassardderick) on May 2, 2016 at 10:40am PDT



#werethetwobestfriendsthatanyonecouldhave ❤️ A post shared by matszuccarello (@matszuccarello) on Jul 18, 2016 at 11:02am PDT

Over the summer, Zuccarello told Norway's VG Sporten that he and Brassard "hung together almost every day" and he was "sad and sorry," but "not surprised" about the trade.

Zuccarello and Brassard did have one prime opportunity to hang out off the ice this season. The Senators visited the Rangers twice, the second encounter coming on Dec. 27, the first game after the NHL's three-day Christmas break. Brassard traveled to New York early to spend time with Zuccarello. Remember, all he wants for Christmas is Zuuuuuc.

#Sens Derick Brassard said he plans on spending Christmas with ex-#NYR teammate Mats Zuccarello. Rangers host Ottawa on December 27. — Sean Hartnett (@HartnettHockey) November 28, 2016

#Sens Derick Brassard on catching up with #NYR Mats Zuccarello over Christmas: "I'm going to catch up and get under his skin a little bit." — Sean Hartnett (@HartnettHockey) November 28, 2016

In a previous life, Brassard and Zuccarello would have posted about their Christmas together on Instagram. But now, as rivals, the social media fun is over. That will be evident Thursday, when the Rangers and Senators open their second-round series in Ottawa. Brassard leads the Senators this postseason in points, with eight, and Zuccarello leads the Rangers in goals, with three. Zibanejad, the Rangers' prize in the Brassard trade, leads New York in points, with four.

Brassard and Zuccarello both have contracts that run through 2019, so a potential reunion is probably at least two years away. However, a public hug should happen a lot sooner. Regardless of how the upcoming series plays out, Brass and Zuc are sure to have an emotional moment in the handshake line after one team is eliminated.

And it will be a reminder that hockey is a business, but friendship is forever.

-- Follow Jeff Eisenband on Twitter @JeffEisenband. Like Jeff Eisenband on Facebook.