I found this article from 2009 when Chicago Blackhawks captain Jonathan Toews was knocked out with a concussion thanks to a Willie Mitchell hit (wasn't suspended). He missed 6 games (about 2 weeks of action). As for long term effects... he went on to be the MVP of the Olympic hockey tournament, as well as winning the Conn Smythe and Stanley Cup in 2010. Just thought I'd post this, in case anyone was looking for some encouragement regarding Sid. Go Pens.