SANTA CLARA, Calif. -- A few days into training camp, San Francisco 49ers fullback Kyle Juszczyk and his offensive teammates were frustrated.

It's common for the defense to be ahead of the offense early in camp, but this wasn't that. It felt different.

"I think the first couple practices, the defensive line just absolutely stood out," Juszczyk said. "They're monsters and I think it took a few days for us on offense to be like, 'OK, we have got to step our game up to match these guys.'"

That kind of evaluation has to be music to the ears of general manager John Lynch and coach Kyle Shanahan, the 49ers' top decision-makers. After all, they have left zero doubt about who and what they are trying to become: a team that relies on a dominant defensive line capable of throwing waves of talent at opposing offenses for 60 minutes or more, if needed.

The Niners now have a defensive line that boasts five former first-round picks after they traded for -- and signed -- end Dee Ford and used the No. 2 overall pick in April's NFL draft on end Nick Bosa. Ford and Bosa join previous Niners first-rounders Arik Armstead, DeForest Buckner and Solomon Thomas.

San Francisco likes its depth behind the first-rounders, with Sheldon Day, D.J. Jones, Ronald Blair III, Kentavius Street and Jullian Taylor capable of filling various roles. There's enough talent that the Niners could take the somewhat unusual step of keeping 10 defensive linemen for fear that they might not be able to stash some of their intriguing youngsters on the practice squad.

On paper, that sounds like a recipe for success, but investing so heavily in one position has undoubtedly created massive expectations that are hard to live up to.

"I think we've kind of finally honed in on who we are, what our identity is going to be," Lynch said. "I think it's pretty clear where we believe you win and lose football games, and you know that group, they need to be dominant."

Those expecting the Niners to make the big leap from 4-12 and the No. 2 pick in the draft to legitimate playoff contender first bring up what the Niners and new defensive line coach Kris Kocurek can do up front.

The thinking goes that adding dynamic edge presences in Ford and Bosa will form a mutually beneficial relationship with Buckner, the only Niners first-round pick to play up to his draft status at this point. Ford offers needed speed and a proven outside rusher who complements the power and technique of Bosa on the other side. If all goes according to plan, Armstead can build on a solid 2018 and Thomas, after enduring devastating personal tragedy last year, can become a versatile piece who can make a difference at multiple positions.

The Niners' belief in their defensive line is so strong that they mostly ignored changing personnel in a secondary that had just two interceptions last season (an NFL record for futility) while finishing second-to-last in passing touchdowns allowed (35) and opponent passer rating (105.4) because they see the pass rush as the best way to improve their coverage.

There's no denying the weight of those suppositions. While each prominent member of that defensive line room, to a man, says that they hold themselves to a higher standard than anyone on the outside, they're being asked to do a lot.

"We look forward to the challenge," Buckner said. "We made some great additions in the offseason. There's a lot of expectations and I think we should live up to those expectations."

Pinning certain statistical benchmarks on the defensive line is probably an exercise in futility, but it's important to note that sack numbers do not a dominant line -- or defense -- make.

For evidence, look at what the Kansas City Chiefs did last season. The Chiefs, led in part by Ford's 13 sacks, shared the NFL sack lead with 52. That didn't mean much, though, because when Kansas City wasn't getting to the quarterback, it was allowing big plays down the field. The Chiefs yielded 32 completions on passes thrown 20-plus yards downfield, the most in the NFL, six of which went for touchdowns. That's in large part due to the Chiefs only contacting the quarterback on 11.5% of dropbacks, the second-worst percentage in the league.

Certainly, San Francisco expects an uptick from the 37 sacks it had a season ago (22nd in the league), but more importantly, the Niners are hoping for more consistent pressure that will force opposing quarterbacks to get rid of the ball faster.

The 49ers were tied for 26th in the league in percentage of dropbacks where they contacted the passer last year (12.1%) and opposing quarterbacks averaged 2.79 seconds before throwing, which was also 26th in the NFL.

Those numbers, along with the Niners' inability to generate takeaways, were at the heart of the team's inability to finish out close games with wins. Over the past two seasons, the Niners have lost 11 one-possession games.

"I never put expectations with regards to stats and all that," defensive coordinator Robert Saleh said. "I don't believe in it. I believe that if you operate at your best every single day, the results that you see will be good, or in the realm in which you expect anyway. For the D-line, the expectation in my eyes is to operate at your absolute best every day with the effort, technique, discipline and violence and trust that whatever result happens will be in your favor. It is a very good group, it is very talented, it is versatile, but you can throw all that in the garbage if they don’t come with that mindset every single day to get better."

Through this training camp, there have been signs of dominance, but also reasons for concern. Ford has missed most of camp with tendinitis in his knee and Bosa's strong start was wiped away by an ankle injury.

Bosa and Ford are expected back soon, possibly in time for Week 1, but their injuries combined with some conceptual tweaks installed by Kocurek have left the Niners mixing and matching along the line rather than building cohesion. Saleh has admitted to being "paranoid" about making all the pieces fit in time to turn the Niners' vision into a reality.

"I want them to wreak havoc on the league," Lynch said. "A lot of our resources have gone there because Kyle and I both believe that you've got to hit the quarterback and you've got to bring him down. I'm more excited than any other time in our time being here with our ability to do that because of some of the moves that we've made ... Now, they've got to go and do it, though."