Mailbag: What did the 49ers learn on Sunday? Any update on Banks and Greenlaw? Can this defense stop top QBs?

We opened up the 49ers mailbag on Monday. You had questions, and we went right to work answering them.

But before we get into it, I have to admit it feels a little wrong writing about football while Buffalo Bills safety Damar Hamlin fights for his life in a Cincinnati hospital. Monday night was probably not the time to discuss football, standings, etc., but life does continue. And so we will do just that, all the while being diligent to remember and pray for Damar and his family. Thankfully, he seems to be improving some.

Let's take a look at the mailbag and see what has been on your mind.

What was the most important lesson for the 49ers to take away from this victory? - Niner Jim

The most important lesson: Don't take any team (or quarterback) for granted. The 49ers did not play well on defense. I realize that's an understatement (although they did come up with a big play in overtime to help win the game).

Kyle Shanahan said he didn't sense a letdown from his team, but Nick Bosa admitted that the defense underestimated Jarrett Stidham. "I think, yeah, a little bit," Bosa said when asked if the 49ers underestimated the Raiders QB, who was making his first start. "But we don't underestimate any team. We come in and we play the best that we can. He played well, so definitely won't underestimate anybody like that again."

Hopefully, that's the biggest lesson they learned on Sunday. And maybe that tough win will propel them to a sixth Lombardi Trophy.

Some other important lessons the 49ers learned:

• Brock Purdy can make plays when the team is down and the game is on the line.
• Mike McGlinchey has been playing really well.
• Deommodore Lenoir has not.
• Brandon Aiyuk is really good.
• Christian McCaffrey is even better.

If the 49ers lose in the playoffs, do you think it will be because of the Pass Defense? - Jeffrey W.

If the 49ers lose in the playoffs, I would expect it will be because of the young QB or the pass defense.

Even though Purdy has played as well as, if not better than, Jimmy Garoppolo so far, the postseason is a different animal. When you're in the playoffs, playing for so much more than you are in the regular season, the pressure is much more immense. The realization that if you lose, you don't play again until the next season, compounds that pressure. That's why so many inexperienced teams and players wilt under the strain of postseason stress. So while Purdy has been playing well, the playoffs will be his biggest test thus far.

The same can be said for the secondary. Charvarius Ward and Jimmie Ward are both veterans with Super Bowl and deep playoff experience. Tashaun Gipson has played in four postseason games in his career, three of those coming in 2017. So he should be prepared for the pressure.

But Talanoa Hufanga and Lenoir are second-year players who mostly played special teams last season. Now that they are starting for the defense, how will they respond?

I think a postseason loss most likely comes as a result of the rookie quarterback or the young secondary. Then again, maybe Purdy and the secondary step up, and the 49ers win the Super Bowl.

Is there any team you don't want SF to see in playoffs (assuming no #1 seed)? Red hot Packers/Rodgers revenge? Seahawks for 3rd time (see 2021 Rams)? - KCarps

Last year, 49ers fans seemed very confident the team would beat the Rams in the NFC Championship Game. I wasn't nearly as confident. Beating a team three times in one season is extremely difficult. I felt like the Rams were due.

With that in mind, I'd be nervous playing the Seahawks again, even though the 49ers should win that game. Of course, the Seahawks are not as good as the Rams were last year, but I'd still be nervous about it.

Aaron Rodgers always scares me. And the Packers are really hot right now. It's impressive that Green Bay is playing so well, considering how horrible they looked for most of the season. The fact that he doesn't have Davante Adams makes me feel better, but Rodgers still scares me.

Detroit's offense scares me, but I don't think their defense can stop anyone.

Dallas is one of the more talented teams, but they're so inconsistent.

The Eagles will be the biggest threat in the NFC. They're loaded. But if Jalen Hurts isn't 100%, they could struggle. So far, they're 0-2 without him. (By the way, I was a guest on a podcast back in July or August, and I predicted the Eagles would be one of the top teams in the NFC. Not to brag or anything!)

Really, it doesn't matter who the 49ers play. They should win. But I'll still be nervous and on the verge of throwing up. That's just how it is.

I know this is looking wayyy too far ahead, but can it be said that this is Purdy's job to lose next season? Even with a healthy Trey, there are still so many unknowns.- Tee

I think it depends on how well he plays in the postseason and how far the 49ers go. If they win the Super Bowl, it's Purdy's job to lose. That may even be the case if they just make it to the Super Bowl.

If the team loses a playoff game, and Purdy is part of the reason, there will be an open competition.

There are three main things to consider with this:

1. Trey Lance is a mystery. Many fans use this fact to rule him out and declare that Purdy is QB1 moving forward. But what if the mystery of Lance turns out the other way? It could be that the massive amount of physical talent he has ends up being too much for a 7th-rounder to overcome.
2. It's still early for Purdy, as well. He's been really impressive so far, but he has limitations. The question is, will his limitations hold him back, or will they simply be a reason he wasn't drafted until the 7th round?
3. Shanahan seems to have more confidence in Purdy than he does in Garoppolo or Lance. The way he calls plays for Purdy shows that he trusts the rookie not to make a back-breaking mistake. That trust could end up giving the edge to Purdy.

It's going to be exciting to see what happens in the playoffs, and next season. I'd give Purdy the advantage, for now, considering how well he's played, and the fact that Lance's second surgery could keep him from doing what he needs to do in the earlier part of the offseason. But that could all change soon. Very soon.

Where did all the Webzone Kyle and John Lynch haters disappear to? I believe they wanted them fired because the team would never be healthy or turn the season around. Play calling sucks...CMC was a mistake...I can't seem to find them anywhere. - Nick V.

Nick, I can't tell you exactly what we've done with them, but if you have seen the show You on Netflix, that might give you an idea.

Actually, that's what happens when you win. It's hard to argue with success. Shanahan and John Lynch have built a great team. They deserve credit and a break from the haters.

When it's working, even critics have to keep quiet, although there are still plenty out there. Trust me, there are always comments and questions that don't make the mailbag. I had one guy tell me on Sunday that Shanahan is the weakest part of the team, and that the 49ers are winning in spite of him.

Another guy asked "when has the 49ers' defense ever stopped anyone with the game on the line?" Umm, how about 2019 in Seattle? How about last January in Dallas and Green Bay? Those are off the top of my head.

So there are still critics out there. And if the 49ers lose in the playoffs, those critics will be back on social media with a score to settle.

That's why I don't get too excited or discouraged. Things can change quickly.

I'm probably slower to declare either Purdy or Lance QB1. I need to see a body of work.

Think about the weeks leading up to the Miami game. Shanahan was a terrible coach, and Mike McDaniel was the brains behind the 49ers' success. People were saying the team should have fired Shanahan and kept McDaniel. Now the 49ers have a chance to be the top seed, and the Dolphins may not even make the playoffs.

The Defense looked suspect vs the Stidham-led Raiders... If and When we do get to the Super Bowl, How do you think the Defense will hold up vs upper echelon QBs like Mahomes, Allen or Burrow in the Super Bowl? - Johnny Y.

That's the question. I think the horrible play of the defense was just a fluke. But stopping some of the top passing teams seems like a much harder thing to do than it did several weeks ago. Losing two of your top three corners will do that.

Someone asked me why Charvarius Ward didn't follow Adams everywhere on Sunday. I told him I wasn't sure, perhaps to just let Lenoir learn. But once the playoffs begin, I fully expect to see Ward shadow the other team's best receivers as he did in Seattle.

Any word on Banks and Greenlaw? - Alan B.

Aaron Banks has a knee and ankle injury. He won't play on Sunday, but he may be ready by the postseason. As Jim Harbaugh would say, it looks like the 49ers "dodged a bullet."

Dre Greenlaw has a back injury and will undergo more testing to determine the extent of the injury. But Shanahan sounded like the injury wasn't as serious as initially feared, and that Greenlaw may not miss any time.

Shanahan also mentioned that Christian McCaffrey is dealing with a mild ankle sprain and is considered day-to-day. But there's a good chance Deebo Samuel and Elijah Mitchell are back on Sunday.

If Jimmy G is good to go at any time during the playoffs, do you think Shanahan will switch QBs?? - Christopher K.

I really think Shanahan will stay with the hot hand. If Purdy is still playing well, he will be the guy. If he's struggling, then maybe Garoppolo would get into the game.

As I wrote in last week's 49ers mailbag, if Garoppolo returns, it likely won't be until later, around the NFC Championship Game. At that point, he would have missed almost two months. You would have to expect that he would be a little rusty.

I wouldn't expect to see Garoppolo play meaningful football in the postseason—unless Purdy starts looking like a lost rookie.

Thanks so much for all your questions. We'll be back next week with another mailbag.