Trades, picks and buyouts highlight a busy first day of the draft

Jake Allen is now the No. 1 for the Blues after Brian Elliott was sent off to Calgary. Rocky W. Widner/NHL/Getty Images

BUFFALO, N.Y. -- The opening day of the draft has become fertile ground for trades both big and small, and Friday's opening round didn't disappoint.

Here's a look at the biggest trades/transactions from an eventful night and why they're worth keeping an eye on.

Calgary Flames acquire goalie Brian Elliott from the St. Louis Blues for the 35th overall pick in 2016 and a conditional third-round pick in 2017

Can Elliott solve the Calgary Flames' significant goaltending woes? And what does the somewhat surprising trade do to a goaltending market already awash in top, veteran goaltenders? Elliott helped guide the Blues to the Western Conference finals with a .921 save percentage. He has one more year left on his contract (the conditional pick will go to St. Louis if Elliott signs an extension with the Flames) and will be a nice veteran presence on a Calgary team that should now be considered an emerging playoff contender in the West. Was Elliott a better option than Ben Bishop, the Vezina Trophy finalist from the Tampa Bay Lightning who is entering the final year of his deal? Or Marc-Andre Fleury, who is a Stanley Cup winner but who lost his job as the No. 1 with the Pittsburgh Penguins to rookie Matt Murray this spring? Calgary GM Brad Treliving definitely didn't overpay for the 31-year-old Elliott. Now, Treliving just has to hope that he backed the right goalie. For the Blues, this puts the pressure squarely on youngster Jake Allen to assert himself as a legitimate No. 1. GM Doug Armstrong will also be looking for a backup. What about free agent James Reimer or perhaps Jonathan Bernier, if the Toronto Maple Leafs eat some salary after acquiring and signing Frederik Andersen to be their new No. 1?

Edmonton Oilers select Jesse Puljujarvi with the fourth overall pick

The established thinking was that Puljujarvi, the other half of the dynamic Finnish forward duo (along with No. 2 pick Patrik Laine) that so impressed scouts, would go to the Columbus Blue Jackets at No. 3. It didn't happen as the Blue Jackets surprised many by taking Pierre-Luc Dubois from the Quebec Major Junior Hockey League. That left the defense-starved Oilers with yet another top-end forward prospect. The implication is that this gives GM Peter Chiarelli even more of a safety net in packaging some combination of Ryan Nugent-Hopkins, Jordan Eberle, Leon Draisaitl or even Taylor Hall for an established top-end defenseman. Does the Puljujarvi pick provide a catalyst for a deal for P.K. Subban or Kevin Shattenkirk? No question, selecting the highly regarded Puljujarvi puts even more pressure on Chiarelli to get something done to bolster the blue line, given his embarrassment of young riches up front.

Chicago Blackhawks trade Andrew Shaw to the Montreal Canadiens for two second-round draft picks in 2016

Yet another piece of the Blackhawks' Stanley Cup machine heads out the door. GM Stan Bowman could not come to terms with Shaw, who is set to become a restricted free agent. The move provides more assets for the Blackhawks, who earlier this month traded 2012 first-round draft pick Teuvo Teravainen to the Carolina Hurricanes for two draft picks. As is often the case with Bowman -- who also had to trade or was unable to sign Johnny Oduya, Patrick Sharp, Brandon Saad and Kris Versteeg from his Cup-winning rosters in recent years -- it's never wise to rush to judge the move, even if it appears that the team is stripping itself down. The Blackhawks won three Stanley Cups from 2010 to 2015, and this move allows Bowman to take a run at keeping unrestricted free agent Andrew Ladd, whom Bowman acquired from the Winnipeg Jets at the trade deadline, or former Blackhawk D-man Brian Campbell, who is also an unrestricted free agent. Marcus Kruger might also benefit from the Shaw deal with a new contract in Chicago.

Montreal Canadiens trade Lars Eller to the Washington Capitals for a second-round pick in 2017 and a second-round pick in 2018

Let's revisit this trade next spring if the Capitals are finally able to shed their playoff demons and embark on a long playoff run, because Eller fulfills an obvious need as a third-line center, playing behind Evgeny Kuznetsov and Nicklas Backstrom. Playing with high-skill players, Eller has 20-goal potential. The Caps' offensive depth, or lack thereof, was a factor in their second-round playoff loss to the Pittsburgh Penguins, even though they ran roughshod over the competition during the regular season while winning the Presidents' Trophy. Eller, 27, has two more years left on a contract with a $3.5 million cap hit.

Detroit Red Wings trade Pavel Datsyuk and the 16th overall pick in 2016 to the Arizona Coyotes for the 20th overall pick, center Joe Vitale and a second-round pick in 2016

So Datsyuk joins Chris Pronger on the Coyotes as they continue to be a receptacle for other team's unwanted cap space. Datsyuk, of course, put the Red Wings in a $7.5 million cap-hit bind when he retired from the NHL this offseason to return to Russia. The Coyotes obviously were interested in moving up in order to grab big, talented defenseman Jakob Chychrun and did dump salary back on the Wings in Vitale. The bigger question is whether the move frees up enough space for the Red Wings to take a legitimate run at Tampa Bay Lightning captain Steven Stamkos, if the sniper becomes available as an unrestricted free agent in July.

Minnesota Wild buy out final season of Thomas Vanek's contract

Vanek illustrates the often risky business of trying to buy a championship, or even a decent playoff run, through free agency. On the plus side for GM Chuck Fletcher, he signed Vanek two summers ago to a three-year deal with an average annual cap hit of $6.5 million. This past season, Vanek continued to reinforce his reputation as one of the most perplexing talents in the NHL with a miserable year, scoring just 18 times and being unavailable for the playoffs due to injury. I wondered if Fletcher would give Vanek a chance to redeem himself under new head coach Bruce Boudreau, but with other pressing needs -- such as signing restricted free agents and needing to find more consistent offense -- Fletcher bit the bullet and bought out Vanek. A team will take a chance on the Austrian-born Vanek, but it will be interesting to see what he will command in terms of dollars and term now that he's an unrestricted free agent. My guess is not much and short, very short.