GREEN BAY, Wis. >> The Green Bay Packers will have to try to win for the first time in more than a month without Aaron Rodgers.

The Packers have ruled out their star quarterback for the game Sunday against the Atlanta Falcons.

“Aaron Rodgers is not ready to go,” coach Mike McCarthy said Friday.

Rodgers hasn’t played since breaking his left collarbone early in Green Bay’s 27-20 loss to Chicago on Nov. 4.

That was the start of a five-game winless streak (0-4-1) for the Packers, whose playoff hopes are fading with a 5-6-1 record with four games to play.

Rodgers practiced on a limited basis this week, including Friday, but still hasn’t been cleared to resume playing.

“Aaron’s frustrated,” McCarthy said. “We’re in meetings all day together. There’s a conversation each and every day. He’s like every other player that’s fighting to get back on the field. He has a rehab program, and how he feels going through it is obviously expressed every day. He’s frustrated.”

The Packers instead spent the week preparing Matt Flynn to make a second straight start at quarterback.

Flynn is looking to bounce back from a rough outing in Green Bay’s 40-10 loss at NFC North leader Detroit on Thanksgiving last week.

“The one thing I need to do better?” Flynn said in response to that question being asked after practice Friday. “Play better. I don’t think you can really look at any one part of what we did as an offense and say we did it well. We need to throw the ball better, and we need to get some completions.”

Flynn completed just 10 of 20 passes for 139 yards with an interception against the Lions. He didn’t lead the Packers into the end zone.

Detroit held Green Bay to a season-low 126 total yards, sacking Flynn seven times.

When asked how he has gone about putting that game in the rearview mirror, Flynn replied, “It’s easy. Just don’t think about it. Just forget about it.”

As the fourth starting quarterback for the Packers this season, all in the last month, Flynn feels more at ease going into Sunday’s game.

Even with Rodgers able to participate in individual drills and do some throwing on the field, Flynn took the first-string reps every day in practice this week. Flynn also had the benefit of a full week of studying the playbook and building a rapport with the rest of the guys on offense.

When he was named the starter for the last game, Flynn had only a few days and very limited practice time to absorb the game plan on the short week.

“It was good just to be able to call the plays,” Flynn said of his work this week. “Now I feel like I’m calling the plays and not really thinking about where guys are lined up or what they’re running. I feel more fluid with everybody, and I feel like we were able to get a little chemistry going.”

McCarthy felt good about Flynn’s progress by the end of the week.

“I thought Matt had a good day today. He missed some things yesterday,” McCarthy said. “I thought he was sharp today.”

Flynn might have to play behind a reshuffled offensive line with center Evan Dietrich-Smith (knee/ankle) questionable for Sunday.

Dietrich-Smith, who turned an ankle in practice Wednesday, didn’t practice the last two days.

McCarthy said the team planned to put Dietrich-Smith through testing for the ankle, which has given him the most trouble the last few days, on Saturday.

“He’s not ready as of today, so we’ll see where he is,” McCarthy said.

If Dietrich-Smith can’t play Sunday, T.J. Lang likely will move from right guard to center.

The Packers would have a few options for filling the void at right guard, having used starting right tackle Don Barclay, Marshall Newhouse and rookie Lane Taylor there for spot duty in recent games.

Rookie left tackle David Bakhtiari practiced Friday after being sent home with an illness the previous day. Bakhtiari is probable for Sunday.

NOTES: Saying his struggling defense needs to tackle better and shore up its recent struggles against the run, veteran coordinator Dom Capers expressed optimism Friday that his group can get things turned around this season. “I think we’re very capable,” Capers said. “It’s got to start this week. We’ve got to go out and it starts by not letting them (the Falcons) run the ball, try to get them in more predictable situations.” The Packers have plummeted to No. 26 in the NFL for run defense, allowing an average of 125.9 yards per game, and are No. 24 in total defense (376.4 yards). . DT Ryan Pickett (knee) practiced on a limited basis Friday after being out a day and is probable. Also probable for the defense are LB Nick Perry (foot) and DE/LB Mike Neal (abdomen). Neal was in practice Friday for the first time this week. . McCarthy said the team would know more about the status of WR Randall Cobb on Tuesday. Cobb is on the injured reserve-designated to return list with a leg injury he sustained Oct. 13. Cobb is eligible to play again Dec. 15 at Dallas. But Cobb said Friday he hasn’t been cleared to start running again.