First period of this Czech game is going to be very interesting.
If Canada is unable to get things going with the new lines offensively, I hope that Dave has it in him to make some necessary changes to revert back to old pairs, combos, etc that has generated offense in the past tourney games. There's no reason to get super cute or experimental even with the Greig injury, which, yes, is a pretty massive blow for this team.
I'm not holding my breath, but let's see what happens.
You don't want to let a team like the Czech hang around and build even more confidence the longer the game stays close. They've already been in a dog fight and faced some adversity in the tourney, especially the USA game.
Canada needs to put their foot on the gas early and never look back.