From the Ottawa Sun:
"Senators prospect Patrick Wiercioch will not be a member of the defending champion Canadian team at this year's world junior championship tournament.
Wiercoch, who was part of the original invite list, is experiencing problems with a "pre-existing" knee injury.
Going to the team's camp in the big defenceman's place will be 67's blue liner Tyler Cuma, who was in contention for a spot on last year's squad before suffering a knee injury at the tryout camp.
Cuma, who was left off this year's list, said yesterday he is "overjoyed" at getting the invite now. "
And here's another article from TSN.
We're going to miss him but also wish him every success.