SANTA CLARA, Calif. -- A quick scan of the roster additions made by the San Francisco 49ers offers hope. Whether it was investing in a dynamic pair of edge rushers, the Day 2 draft focus on the receiving corps or even an emphasis on improving at punter, the Niners have a lot of new blood across the board.

Almost.

Noticeably ignored this offseason is a secondary that accounted for just two interceptions in 2018, an NFL record for futility. Aside from adding oft-injured cornerback Jason Verrett in free agency -- who, in fairness, could be a big addition if he can stay healthy and recapture his 2015 Pro Bowl form -- the 49ers look poised to run it back with the same group they had last season.

This lack of movement in the secondary comes as a surprise. Verrett was the only notable free-agent pickup and the Niners waited until the sixth round before they took cornerback Tim Harris. Despite rumors that the team pursued a top safety such as Earl Thomas, the 49ers didn't bring in any outside safeties, instead opting to re-sign Jimmie Ward and Antone Exum Jr.

According to coach Kyle Shanahan, the decision to leave the secondary alone stems from liking what they already have, the importance of improving other roster spots and the hope that a supercharged pass rush can make life easier for everyone.

Clearly, the 49ers' decision-makers are believers in the talent already in place. While many of their young defensive backs have flashed in their careers, the majority of them have been plagued by injuries, have a small sample of success or both. As it stands, the projected starters in the secondary are cornerbacks Richard Sherman and Verrett, with Ward and Jaquiski Tartt at safety and K'Waun Williams in the nickel role.

From that group, Sherman is the leader and the Niners are counting on him to produce at previous All-Pro levels. His history would indicate that he can do that now that he's another year removed from the Achilles injury he suffered in 2017.

"I look out my window, and he's getting up there in years, but he's right at the front of the pack," general manager John Lynch said. "He's pushing those guys. I think my own feeling, we'll see a better version of Richard Sherman this year because he's a year further away from those procedures and had that cleanup. We'll see. But I'm hopeful.”

After Sherman, questions arise. The Niners invested third-round picks on Ahkello Witherspoon and Tarvarius Moore in the past three years but neither has emerged as a surefire starter opposite Sherman, which is why the door is open for Verrett. At safety, Ward and Tartt have combined to play just 33 of a possible 64 games over the past two seasons. Adrian Colbert, who was supposed to claim the starting free safety job last year, struggled in seven games before a season-ending ankle injury.

In a vacuum, the Niners' belief in their current crop of defensive backs is understandable. It's a group comprised of relatively high draft picks and there's no shortage of talent. But it's also fair to point out that the Niners felt good about what was essentially the same group a year ago and then found themselves scrambling to overcome injuries and a lack of production.

So why did the Niners choose not to spend a draft pick on a defensive back until their last pick of Round 6?

Shanahan said it's a matter of weighing how much any new addition could contribute. For example, if the Niners had gone with a corner in the second round instead of receiver Deebo Samuel, would that corner have been a strong bet to start over the other corners? Or, more precisely, would that corner have been more likely to start than Samuel is at wideout? The Niners also passed on the chance to throw another mid-round dart at a developmental corner to take punter Mitch Wishnowsky in the fourth round.

Those are the sort of value propositions the Niners took into account in waiting to draft a defensive back.

“You try to improve your team wherever you can," Shanahan said. "You look at our secondary now and everything, and it's not the easiest thing in the world to go draft a guy who can just come in and beat out Richard Sherman, Jason Verrett, Ahkello, Tarvarius Moore. Those aren't easy things. And you look at other positions and stuff. So, that goes to each round."

The other primary reason the Niners didn't significantly address the secondary is because they believe that they improved that group by bolstering the pass rush with edge rushers Dee Ford and Nick Bosa. In 2018, the 49ers were tied for 22nd in sacks with 37 but ranked just 31st in times contacting the quarterback (80), and opposing quarterbacks averaged 2.79 seconds before throwing, which was 26th in the league.

Although the Niners were able to generate pressure at a middling level, too often they found themselves allowing opposing quarterbacks time to push the ball down the field. And while sacks are a good thing, they aren't everything when it comes to helping out a secondary. The Chiefs tied for the NFL lead with 52 sacks, but they also had 89 pass attempts of 20-plus yards against them, the second most in the NFL. So while Kansas City was able to bring down the quarterback, the times when they didn't often led to big-play opportunities.

All of which is why the 49ers' focus isn't just on generating more sacks but on making the quarterback get the ball out quicker and making it uncomfortable for him consistently when he doesn't.

The hope is that Bosa and Ford will allow for more chances at interceptions, something the Niners didn't do in 2018.

"I don't think we dropped too many [interceptions] as a whole, which that should tell you something," Shanahan said. "We've got to cause more havoc on that quarterback so he throws some wild passes that do come to us."