Vainonen, 19, spent his first season with the Kingston Frontenacs in the CHL, and the native of Finland was fourth among defencemen with 22 points. He also was the captain of Finland's team at the 2012 U-18 World Championships.
He was the Predators' sixth selection in the 2012 draft at No. 118 overall in the fourth round.
It's not always going to be pretty, especially against a great goalie [Lundqvist] like that. My goals are never how you draw them up. It's just a matter of grinding it out and trying to create havoc in front and good things happen.
— Capitals forward Jay Beagle on scoring in their Game 3 victory against the Rangers on Monday