It’s do-or-die time for the Green Bay Packers. As of this writing, they’re 7.5-point underdogs. The line began at -7, which means even with a touchdown advantage, bettors still see the 49ers as the better bet.

There’s logic to see it that way. Back in November, we covered many of the reasons why 49ers are a problem, and those reasons remain unchanged today: George Kittle is an elite tight end and matchup problem; the defensive front four has the most top-to-bottom talent in the league; Fred Warner plays with his hair on fire (and their other linebacker, Kwon Alexander, is back from injury); their offensive system challenges you in multiple ways.

The Packers failed the first test. Can they pass the second?

Analysts, specifically YouTube NFL analyst Brett Kollman, point to one main reason for concern: predictability on defense.

Paraphrasing, Kollman details how defensive coordinator Mike Pettine tends to telegraph his coverages via personnel, which is no bueno for an offensive mind such as Kyle Shanahan’s.

It’s worth noting, however, that the Packers have since improved on many of the issues Kollman discussed since the 49ers game. Since Week 12, the one notable “poor” defensive performance was against Detroit, which was more the exception than the rule in the final month and change of the season.

One reason for the improvement was the return of Ibraheim Campell, who filled the void left by Raven Greene after he went to injured reserve in Week 2. Campbell is the chess piece Pettine needs to keep correctly balance the need to stop the big pass without being too vulnerable against bigger offensive personnel. Campbell gives the Packers speed in the middle of the field and also puts Adrian Amos back into his more natural position.

The second and more important reason is communication. Lest we forget how young this defense is, especially the back end: Darnell Savage is a rookie, Jaire Alexander is in his second season, Kevin King is in his third season, and Adrian Amos is in just his fifth NFL season. Tramon Williams is the lone elder statesman.

Generally speaking, this defense is green, an attribute of which the Niners took advantage.

The beatdown in Santa Clara did help the Packers in one way, though: it catalyzed this group into holding each other accountable.

According to Packers News, less than a day after the game, the defense called a meeting, sans coaches, and pored over the film.

Said linebacker Blake Martinez of the players-only session: “As we were going through the plays, it became evident that certain guys in certain position groups thought they were doing the right thing, certain guys from other position groups thought they were doing the right thing. And throughout the whole time we were watching, it was like, ‘Oh, I thought I was supposed to be doing this.’ Or, ‘Oh, I thought I was supposed to be doing this.’

It makes sense, too. We noted in our Week 12 film review how the Packers haven’t communicated well, among other things, and that it might be time to play a little more man coverage. If, like Kollman suggests, the Packers are predictable, changing up coverage and relying a little more upon Jaire Alexander and Kevin King as athletes might be enough to keep Shanahan and Jimmy Garoppolo on their toes.

This is going to be a tough game one way or another. More than likely, it’s going to be closer than many think.

Film Notes:

• Tight end George Kittle makes this offense work. He’s an elite athlete capable of blocking (and dominating) in one-on-one situations. He’s too big for corners and safeties, and he’s too fast for linebackers. The Packers might look to limit Kittle by chipping him off the line. That may undermine their pass rush some, but we’ve seen the alternatives.
• The 49ers receive their top tackle, Joe Staley, back. He didn’t play in the last outing. Staley is quick out of his stance and plays with enough power to set the anchor.
• Kyle Shanahan and quarterback Jimmy Garoppolo have been operating a mind-meld this year. Shanahan dials up passes that seek to simplify the reads based on a defense’s personnel and pre-snap coverage read. Garoppolo is sharp enough mentally to make the right read and the quick throw. Their first red-zone trip against Minnesota last week was an example of this. In a 2-by-2 set, with Kittle in the slot, Garoppolo read man coverage as Anthony Barr flew to the flat to cover Deebo Samuel, who leaked out to the flat from an orbit motion. As Barr vacated his zone, Garoppolo targeted Kittle on the post before the other linebacker, Eric Kendricks, could replace. It’s a bang-bang play.
• The safeties have to play smart football Sunday. Anthony Harris ceded a touchdown when he got caught peeking in the backfield. It was enough for Kendrick Bourne to find open space in the back of the end zone. The cornerback gave leverage inside expecting help, but Harris’ positioning created a small void in the zone.
• It’ll be interesting to see how the 49ers defend the interior without defensive tackle D.J. Jones. He wrecked Corey Linsley in the last meeting. Though Arik Armstead and DeForest Buckner can slide to three, they’re longer, leaner frames for a nose. It might be an opportunity to get push inside.
• At times, Jimmy Garappolo can deliver some questionable throws under duress. He’s most vulnerable to inside pressure (as most quarterbacks are). He gets the ball out quickly, but the Packers would be wise to increase the volume and diversity of their blitz package. They can simultaneously clog run lanes and also force quicker throws on play-action.
• The speed of the 49ers’ off-ball linebackers makes life difficult in multiple ways, but one specific way is getting yards after the catch on underneath throws and screens. They’re space-erasers.
• Rookie Nick Bosa, if healthy, will be in that All-Pro conversation next year. He’s extremely athletic and strong. He’s also plenty to big to be an effective three-down player.
• The Packers may want to consider cutting at the line of scrimmage, especially on the backside. It could mitigate cutback lanes, but the benefit is you keep the pursuits of the Niners’ top four linemen honest.
• The Packers’ interior defensive line needs to be on their A-game. It’s hard enough to transition from run fits to an effective pass rush, but it’s easier when you can control the line of scrimmage. The Packers can solve a lot of problems if Kenny Clark and the rotations of Dean Lowry and Tyler Lancaster make it hard for the center and guards to coast to the second level. That happens by occupying blockers and playing on the opponent’s side of the line of scrimmage.
• Blake Martinez needs to get depth on his zone drops this week. The Niners excel at finding space between the safeties and the hook/curl ‘backers. Garoppolo is quick with his reads and throws with enough accuracy to exploit the voids in the zone. Kendricks intercepted Garoppolo precisely because he started getting deeper on his drops.
• Shotgun sets with empty formations are generally bad news against the 49ers. They need to only rush four is most situations. Longer-developing routes and Rodgers’ tendency to hold onto the ball is a recipe for disaster. At the very least, Matt LaFleur needs to give Rodgers underneath outlets. Even with five wide, the 49ers have seven in coverage, so Davante Adams will likely be doubled.
• Look for the Packers to get Rodgers out of the pocket on play-action rollouts more frequently. Though it might limit the field reads, it’s a way to avoid the 49ers’ pass rush. Packers should also try to hold linebackers accountable with pre-snap jet motion, orbit motion and split zone play-action, where tight ends or slot receivers come across the line sometimes as blockers and sometimes as receivers. LaFleur needs to keep San Francisco honest; otherwise, they’ll pursue downhill with fire and fury.