Should the 49ers make changes in the secondary or stick with the same starters?

Weather played a factor, but a couple of players didn’t play well. Is it too reactionary if the 49ers made a change?

It feels like you’re selling the Green Bay Packers short with their performance against the San Francisco 49ers when you say there’s nothing to worry about with the ‘Niners’ defense moving forward.

There were five plays where the primary defender slipped, leading to a Packers first down or touchdown.

It was bizarre watching the 49ers being affected by the field conditions as much as they were and not Green Bay — especially with the game being played at Levi’s Stadium.

The forecast for Sunday afternoon only has a 12 percent chance of precipitation, according to AccuWeather. It’s supposed to be 72 degrees. The footing issues we saw from the 49ers defense were extreme outliers. It hasn’t happened before and there’s no reason to believe it’ll happen again.

Staying in structure

Dre Greenlaw, Fred Warner, Arik Armstead, Deommodore Lenoir, Javon Kinlaw. Those were the five best 49ers defenders. They were all outstanding and made play after play when called upon.

Warner led the team with six run stops. Lenoir had four, and Greenlaw had two. Nick Bosa made a couple of hustle plays when he chased Aaron Jones down the line of scrimmage. As a team, the 49ers held the Packers running game in check. They generated a negative EPA per play rushing the ball, and that includes Jones’s 53-yard run.

But there were a couple of plays where the Packers used the Niners aggressiveness against them — primarily to Chase Young’s side:

Young did the same on a reverse later in the game, where he gave up the edge and was nowhere to be found. That’s something Lions offensive coordinator Ben Johnson will likely try to do in the NFC Championship game.

When the 49ers played in the structure of the defense against the run, they were sound and made plays. But there were a handful of examples of that not happening, and the Packers made them pay for it.

Oh, Ambry

Saturday night was a game to forget for Ambry Thomas in coverage. Kyle Shanahan was asked what the coaching points for Thomas would be this season. Here’s what he said:

“They’re all different. You can’t grab guys. So, it has to do sometimes with staying closer to them so you don’t grab them when they make the second move. So, that could be on one. The other one down the field, yes, that’s not all on him. He needs a little bit more help and stuff.

But in that down and distance, you’ve got to stay on top of that so you can flatten things when you’re digging out from behind. Any balls underthrown like that, it’s extremely, extremely hard to avoid contact with the receiver going up for the ball. So he’s got to make sure to get himself in better positions before he ends up in that tough position.”

You better believe Thomas will have a bullseye on his back against the Lions and whoever the 49ers play in the Super Bowl if they advance.

Lenoir looks confident and sure of himself in coverage, while Thomas looks like he has no idea what’s coming his way or how to react. Lenoir is calm and cool when the ball is in the air while Thomas presses the panic button.

The play below, where Thomas and Lenoir defend the same route at different levels, speaks to their situational awareness. It’s third down:

One player is in a perfect position exactly where he needs to be, while the other is not.

Veteran or the youngster?

The coaching staff rolled with Sebastian Joseph-Day out of the gate over Javon Kinlaw. Joseph-Day missed a tackle and got pushed around while the Packers moved the ball. He ended up playing ten snaps, with most of those coming on the first two drives.

Kinlaw split double teams, reset the line of scrimmage, and made multiple plays. Shanahan has a propensity to give the veteran the nod over a younger player or a rookie. That was the case here, and he was wrong.

Safety Ji’Ayir Brown missed time with a knee injury, opening the door for Logan Ryan to start. Ryan had a pair of missed tackles that were enormous. He also had a busted coverage that led to an explosive play. And while Ambry will get plenty of hate for his 3rd & 15 pass interference, Thomas left him out to dry.

The 49ers were in Cover 4 — a coverage they ran at the fourth-highest rate in the NFL during the regular season and allowed the fourth-lowest yards per attempt. There are two receivers on Thomas and Ryans’ side. One stays in and blocks. Instead of helping Thomas out, Ryan, for whatever reason, looks to the other side of the field.

Here’s the play:

I understand he’s a veteran with experience and has played in the biggest games, but Ryan made multiple egregious mistakes. The 32-year-old is in the game over Brown because he’s supposed to be “safer” and not have coverage busts.

Shanahan explained the decision to go with Ryan over Brown after the game:

“We knew that we kind of decided that when Ji’Ayir had missed about four weeks. I think it was two games, but he had been out four weeks. He’s been awesome in practice. I love Ji’Ayir. It has nothing to do with him. Just our experience of playoff games being around us.

I think it’s a lot when you got a rookie who hasn’t played in a month, who is a very passionate, aggressive player. I just don’t want to put all that on him, to have him go out in the playoff game when he hasn’t been out there for four weeks. Especially when you have a veteran behind him who could just calm down a little bit. If things would’ve gone differently, we would’ve put Ji’Ayir in right away. But we don’t want to do that really to Ji’Ayir.”

It’d be an impulse decision to make multiple changes in your secondary when you’re in the NFC Championship game, but there wasn’t a lot to like from Thomas and Ryan.

Thankfully, players like Greenlaw and Warner stepped up and made their poor play moot. The 49ers have a decision to make against the Lions, as they may not be as fortunate this time around.