Mitchell, 30, recorded 13 points (6 goals and 7 assists) in 51 regular season games with the Sabres in 2014-15, averaging 15:20 minutes of ice time per game. He produced two game-winners and was assessed 26 penalty minutes.
Baertschi had four assists in 15 games with the Flames this season. He had eight goals and 25 points in 36 games for Adirondack in the American Hockey League.
"In this case, we feel like Sven Baertschi is going to be a top-six [forward], NHL player for our team someday, so we weighed getting Sven versus what we would get in the second round with our pick and we made the decision to go ahead and do it," Canucks general manager Jim Benning. "He's a guy that fits our profile. He is fast, he is skilled. ... We are very happy to have him."
Smith, 26, has five goals and four assists in 61 games. A sixth-round pick (No. 169) in the 2008 NHL Draft, Smith has 23 goals and 39 points in 156 games spread across parts of five seasons.
Last season Smith had career-bests of 14 goals and 26 points in 75 games, and six points in 19 Stanley Cup Playoff games.
"When a top nine player gets injured, we didn't really have a player that could slide up and play consistently there," St. Louis general manager Doug Armstrong told the Blues website. "Olli wanted to go to a team that he felt had a chance to win. He wants to win a Stanley Cup, and he’s willing to take whatever role; he’s 100 percent committed to doing whatever he can do to be a great teammate."
Louis, 27, has appeared in 34 games for the Portland Pirates of the American Hockey League this season, recording three assists and racking up 77 penalty minutes. The 6'4, 229 pound blueliner played 174 career AHL games, all with the Pirates.
Leopold has one goal and two assists in 25 games this season for the St. Louis Blues and Blue Jackets. Born in Golden Valley, Minn., he won the Hobey Baker Award in 2002 as the nation's top collegiate player while attending the University of Minnesota.
If Tampa Bay fails to make the Stanley Cup Playoffs in 2015 and get the first pick in the draft, Philadelphia will receive the New York Rangers' 2015 first-round pick, acquired last season as part of the Martin St. Louis trade, in lieu of Tampa Bay's first-round selection.
Coburn has one goal and eight assists in 39 games this season. He has one more season remaining on the four-year contract he signed in November 2011.
"I'm excited to go to Tampa Bay," Coburn said on TSN. "They've got a great team. Little sad to leave Philly but I'm looking forward to getting down to Tampa."
Connolly, 22, has 12 goals, three assists and 38 penalty minutes in 50 games this season.
He said he was informed of the trade early Monday morning.
"I heard about it at about 1:30 a.m., I was a little surprised but that's the business and you know anything can happen," Connolly said. "I really enjoyed my four years with this organization and I thank them for the opportunity and I'll miss the teammates, the city and the fans. I'm looking forward to the opportunity with Boston."
Cole, the 18th pick in the 2007 NHL Draft by the Blues, has four goals, nine points and a plus-16 rating in 54 games this season. He has nine goals, 31 points and is plus-40 in 167 regular-season games over parts of five seasons.
"You're always hoping for more, but you look at St. Louis' defense and that's a very experienced, almost star-studded defense. So, you can understand why sometimes he may be in and out of the lineup," Penguins GM Jim Rutherford said. "He brings good depth to our blue line. He's had a very good year this year and we hope that continues here."
Introducing the new official NHL App, available for iPhone, iPad and Android smartphones and tablets. A host of new features and improved functionality are available across all platforms, including a redesigned league-wide scoreboard, expanded news coverage, searchable video highlights, individual team experiences* and more. The new NHL App on your tablet also introduces new offerings such as 60fps video, Multitasking** and Picture-in-Picture.
*Available only for smartphones
** Available only for suported iPads