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.
There's not much to say. We played like [garbage]. I think every guy in the room should be completely embarrassed about how they played tonight. Every single person. To start a road trip, one of the biggest road trips and have a division rival chasing you down and have a ton on the line, it's ridiculous how we played tonight.
— Anaheim forward Andrew Cogliano after the Ducks' 7-2 loss to the Flames on Wednesday