As Vogl pointed out in his article, the Sabres have 26 guys at camp. They need to get down to 23 by 3pm Friday. If you put Gerbe and Cody on IR you're down to 24.
My question is do they really need to waive someone right away? Technically Grigorenko's contract doesn't kick in until the 6th game, so is it really counted? If it doesn't, they don't need to waive anyone until Gerbe or McCormick come back or before Griggy's 6th game.