Speaking Friday morning, a day after the Packers were embarrassed 40-10 by the Detroit Lions, McCarthy feels the Packers must win their remaining four games.
"I would think so, yes," McCarthy said.
Even that might not be enough to get the two-time NFC North champions back in the playoffs. Winless in its last five games (0-4-1), Green Bay is in a big bind going into the final month of the regular season. The Packers have tumbled from the top of the division to third place with a 5-6-1 record.
Not only is Green Bay trailing NFC North leader Detroit (7-5) by 1 1/2 games, the Packers have never reached the playoffs with a sub-.500 record after 12 games since the NFL expanded the schedule to 16 games in 1978.
McCarthy didn't downplay the predicament facing his team.
"Oh, we're in a hole," he said. "We felt like we were in the hole going into the Detroit game. We've got two division losses and a tie. That's not where you want to be."
The Packers are in danger of missing the postseason for the first time since 2008, when they had a five-game losing skid late in the season and finished 6-10. That was Aaron Rodgers' first year as the team's leader on offense.
"It's pretty hard to get any lower than right now after a terrible loss on national television, but we have to keep going," linebacker Clay Matthews said after Thursday's game. "We still have four games left — a whole quarter of the season. We've got to finish strong. We'll take some time to reflect on this loss and get away for a few days and come back and have an Atlanta team at home."
Green Bay doesn't play again until it hosts the last-place Falcons on Dec. 8, but McCarthy isn't sure if Rodgers will resume playing then. The star quarterback has missed the last four games because of a broken left collarbone.
Rodgers was cleared to practice on a limited basis earlier this week and did some throwing on the field Tuesday and Wednesday.
When asked Friday whether Rodgers has a chance to play against Atlanta, McCarthy replied, "I don't know that."
"I just know when we came off the field Wednesday that he wasn't ready to play yet," McCarthy added. "So, we'll see how the testing goes. But it needs to be the right thing. I know he wants to play, I know he's trying to gear up each and every week to play, but we'll see what happens next week."
Feeling the sting of the Packers' most lopsided loss since they fell 35-0 at home against New England in McCarthy's first season as coach in 2006, at least one frustrated player commented on how much Rodgers has been missed.
Green Bay didn't have a victory in its five November games after Rodgers went out after the first series of the loss to Chicago on Nov. 4. The last time the Packers were winless in a full month of games was December 1990, when they went 0-5.
"It definitely made things a lot more difficult without Aaron," left guard Josh Sitton said Thursday. "I think we all know that. There's no denying that. You can't say, 'Hey, we can go and play just as good without Aaron.' We haven't won a game without him in five weeks. He's the best player on this team. Yeah, we need him, but there's a lot more going on than just that."
Indeed, the Lions exposed the shortcomings for an injury-depleted Green Bay team in several areas.
"It was a very convincing win by the Lions," McCarthy said.
The statistics reflected the one-sided outcome.
Detroit outgained the Packers 561-126 in total yards and had possession of the ball for more than twice as long: 40 minutes, 26 seconds to the Packers' 19:34.
The Lions also gashed Green Bay for 241 yards rushing four days after the Packers allowed a then-season-high 232 yards on the ground in their overtime tie against Minnesota.
Detroit accomplished all that despite turning over the ball four times. The Lions scored 37 unanswered points after a strip-sack by Nick Perry resulted in a short touchdown return by Morgan Burnett that put the Packers up 10-3 early in the second quarter.
McCarthy noted an estimated 20 missed tackles by Green Bay's defense and coverage units on special teams.
"You get above 10 missed tackles in a game, that's a long day," McCarthy lamented.
A sputtering offense certainly added to the Packers' holiday misery. Led by their formidable front line, the Lions sacked Matt Flynn seven times and held Green Bay to a season-low 24 yards rushing.
Flynn, the fourth starter at quarterback for Green Bay in the last five games, also had three turnovers.
"We got drilled by a very good football team that played very well," McCarthy said. "So we'll take that hard lesson, swallow, they'll be accountable for it, and we'll be ready to go when Atlanta comes in here."