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."
"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.