Unbeaten 49ers keep surprising each week

SANTA CLARA - Lots of people thought the 49ers would be good this season.

Not many thought they'd be 5-0.

Sure, the schedule broke in their favor. They haven't faced a good quarterback yet, because Ben Roethlisberger had season-ending elbow surgery and missed the Steelers' Week 3 game against the 49ers. The highest-rated quarterback the 49ers have faced is Roethlisberger's backup, Mason Rudolph. And the best team the 49ers have faced is the Rams, who are 3-3. Bigger challenges will come soon.

But the 49ers seem ready for the challenges. They've outscored opponents by 16.6 points per game - second best in the NFL. They've improved dramatically. They might even be Super Bowl contenders.

Here are five things we didn't necessarily know about them until now:

1. The defense might be great, not just good.

We knew the defense probably would improve. Hard to know it would improve this much.

Last season, it gave up 27.2 points per game - fifth most in the league. Solomon Thomas, a former first-round draft pick seemed like a bust. Arik Armstead, another former first-round pick, seemed expendable. And defensive coordinator Robert Saleh seemed on the verge of getting fired.

This season, the defense has given up 12.8 points per game - second fewest in the league. Thomas and Armstead both have played well, and Robert Saleh seems like a future head-coaching candidate.

Washington Redskins interim head coach Bill Callahan broke down the 49ers' defense Wednesday morning on a conference call with Bay Area reporters. “Everything about it says speed, explosiveness, quickness, ability to redirect and generate pressure from all different angles and alignments. We're going to need a lot of help, to say the least. This is one of the best units I've seen so far this year.”

During the offseason, the 49ers added three key players: linebacker Kwon Alexander and defensive ends Dee Ford and Nick Bosa. Now, the 49ers have an excellent linebacker, plus five former first-round picks on their defensive line: Ford, Bosa, Armstead, Thomas and DeForest Buckner.

“They've got the full package,” Callahan said. “When they line up across the board, there's just not one individual that you can hone in on. Like when we played the Bears, you have Khalil Mack that you're focused on. This is a little bit different because there's so much quality depth and outstanding players.”

Who could have expected the 49ers to have a better defense than the Bears?

2. The defensive backs actually are good.

Last season, the defensive backs were seen as the team's biggest weakness. They gave up an average quarterback rating of 105.4, and set the NFL record for fewest interceptions in a season. They recorded only two.

During the offseason, the 49ers brought back all five starting defensive backs - Richard Sherman, Ahkello Witherspoon, Jimmie Ward, Jaquiski Tartt and K'Waun Williams - a move that seemed crazy at the time. But through five games, the 49ers already have intercepted seven passes and allowed a miniscule quarterback rating of just 62.5.

Suddenly, the 49ers have one of the best defensive backfields in the league. It's good even when backups replace starters.

Jimmy Garoppolo knows how good the defensive backs have become - they intercepted him on five straight passing attempts during training camp. “There were no easy throws like in the past, where you could have an easy one outside or something like that,” Garoppolo said. “Everything was contested. Everyone had tight coverage - man to man, zone, whatever. That, tied in with a good pass rush, makes it tough on a quarterback.”

Meaning the major investments on the defensive line have allowed the existing players in the defensive backfield to reach levels many didn't know they had.

3. The 49ers are a run-first team.

The 49ers have carried Garoppolo this season. We thought it would be the other way around when they traded for him.

“They've done a great job managing his game,” Callahan said.

The 49ers didn't manage Garoppolo during his five-game win streak in 2017. He was the best player on their offense, the reason they won games.

We thought he would develop into a prolific passer as he gained experience. But he's not a prolific passer, not yet.

He ranks 21st in passing yards this season, and the 49ers rank first in rushing attempts per game. Garoppolo is along for the ride, perhaps because he's still recovering from a torn ACL.

“They're committed to running the ball,” Callahan explained. “The big thing for us is the run-action shots off of their running game. That's where the potency lies in their offense. They lean on that run, and they can hurt you bad in the run-action passing game. That's a huge challenge and something they do very well.”

4. Kyle Shanahan has grown from an offensive coordinator to a head coach.

Shanahan has two jobs: head coach and offensive coordinator.

The past two seasons, at times he seemed more like an offensive coordinator than a head coach, and the 49ers played like a team without a leader. He was focused on installing his offensive system, and the 49ers lost lots of close games.

Now, his system is in place, and he's focused on winning by any means necessary. “I've learned how to balance things,” Shanahan said. “It has gotten easier for me over three years to see when it's more important to focus on fixing X's and O's, and when to focus on talking to people and making people alright.”

Shanahan has become the leader the 49ers needed.

5. Shanahan has grown as an offensive coordinator, too.

Shanahan is known for coaching a simple running game which features an outside-zone blocking scheme. It looks like five offensive linemen and a tight end moving together in a conga line.

If the majority of Shanahan's run game were merely zone runs, the 49ers' offense would struggle this season, just as the Rams' offense has struggled. The Rams rely heavily on that blocking scheme, and defenses around the NFL have caught up to it.

Shanahan has remained one step ahead.

“They run the zone game still - that's a staple of Kyle and his father, Mike,” Callahan explained. “That will always be a staple when he's at the helm. But they've mixed in a little bit more gap schemes, and they've really taken their system into the new age with all the jet-sweep motions and things of that nature. It's really diverse, it's really challenging.”

Suddenly, Shanahan has one of the most sophisticated running games in the NFL. In his 12th season as an offensive coordinator, he's still growing and improving.