GREEN BAY, Wis. -- Don’t be surprised if the Green Bay Packers come to play Sunday in a manner in which they didn’t one week earlier, when their embarrassing home loss to the Arizona Cardinals led to coach Mike McCarthy’s firing minutes after the game.

"Most of the time, in situations like this, you’ll see players play their ass off," a longtime NFL agent told ESPN.com. "They want to show everyone, ‘Hey, we weren’t the problem.’"

Their chance to do so comes Sunday at Lambeau Field against the Atlanta Falcons, the first game of the interim coach Joe Philbin era.

"I’d be surprised if they didn’t come out and play hard," Packers defensive coordinator Mike Pettine said this week. "I mean, they understand it’s part of the business, and I know a lot of them were very surprised, shocked by it. But at the end of it, and we talk about it in our meetings all the time -- this was even before this happened -- you’re in charge of everything you have full control over and that hasn’t changed. Their preparation, whether it’s the physical, the mental, how they practice, how they take the game plan and apply it to the field, that hasn’t changed. A big part of what we do is dealing with adversity, test of mental toughness. I mean, if you want to win, you have to be mentally tough. I don’t know if there’s any bigger test of that than this week."

But the idea of playing extra hard because of it didn’t sit well with Pettine.

"That means we had some in reserve, and you certainly don’t want that to be the case," he said. "I guess I’ve been around enough situations or seen them from afar to know I don’t know if it’s very predictable what you’re going to get. We’re having a good week so far and we’ll see on Sunday."

That’s exactly how veteran receiver Randall Cobb sees it, saying: "I would never change the way I play because of a situation."

It's been a week in which almost none of the external focus has been on the players and almost all of it in on the coaches. Players worked Monday while team president Mark Murphy and general manager Brian Gutekunst explained the decision to fire McCarthy with four games left in his 13th season as head coach. On Tuesday, Philbin fired longtime assistant coach Winston Moss, the final straw coming when he posted a tweet critical of the organization. On Wednesday, McCarthy returned to Lambeau Field and delivered an emotional farewell to his former players.

"I think we all share in the responsibility," quarterback Aaron Rodgers said. "That’s the toughest part. The players are the ones who are playing. Obviously coaches have responsibility to prepare and teach and demand, but the players on the field are performing and obviously our performance level wasn’t such that we could keep Mike in his place."

This week, Philbin altered some of the practice structure. For example, on Wednesday he started practice with the fast-paced fundamental drills and a special-teams period rather than the lengthy jog-through sessions in which the offense works against the scout-team defense and vice versa.

"If yesterday's practice and today's practice is any indication, I'm excited," special-teams coach Ron Zook said Thursday. "I look forward to it. These guys are professionals. I think they all are very fond of Coach McCarthy. … But they understand, it's a business. I think some of the young guys are like, 'Now I know what you're talking about, Coach.' You're not promised tomorrow. I think everybody wants to go out there and do the best that they can."

The Packers (4-7-1) opened the week as six-point favorites over the 4-8 Falcons, according to the Westgate Las Vegas SuperBook. By the end of the day Thursday, the line had moved slightly, to 5.5 points.

"I think these last couple of games, it’s going to be a lot of that -- just showing guys our heart and the fight and just playing for Coach Philbin and all those type of things," third-year defensive tackle Kenny Clark said. "Just because I mean it’s tough and you know we had a couple of rough stretches during the season. Anytime we can show that, it would be good.

"Anytime you go out, you’re trying to play for your teammates and I just think it’s important for us these last couple of games just to play for each other given all we went through."