McCarthy's defense has come under fire following the result, in which their opponents were able to steal 1,037 yards on the ground, with the Packers giving up a season-high 241 yards at one point in the game.
"Scheme is not a crutch. When you're in run defense, you play with leverage," said McCarthy, according to ESPN.
"You've got to get off the damn block and tackle the ball carrier. You can cut it any way you want, and we're not doing that right now. We haven't done that in a month."
Thursday's defeat now leaves the Packers in third position in the NFC Northern Division.