SANTA CLARA, Calif. - The 49ers have made it abudantly clear they're doing everything they can to put their offseason behind them and move on with a clean slate.
Yes, they lost a number of key players, including Patrick Willis, Aldon Smith, Chris Borland, Justin Smith, and the two cornerbacks to free agency that saw the most playing time in 2014 in Chris Culliver and Perrish Cox.
But after Monday night's 20-3 win over the Vikings, when the defense controlled Teddy Bridgewater and held Adrian Peterson to 31 yards rushing, San Francisco is feeling good about the group of new players stepping into prominent roles left behind by those veterans.
"Just as many people as we lost, we gained just as many people," new starting cornerback Kenneth Acker said. "A lot of people got a lot of opportunities to step up, just like myself. Everybody had a role."
The starting cornerback spot opposite Tramaine Brock had been a mystery coming into the season with new head coach Jim Tomsula tight-lipped about how he'd distribute playing time within his new-look defense. Acker was one of four candidates to see time with the starters in August.
Acker had a strong preseason, leading NFL corners with a 7.8 passer rating when targeted, according to Pro Football Focus (his teammate, Dontae Johnson, was second at 9.8).
Elements of Acker's rise to the starting lineup were both expected and surprising. He had a strong training camp as a rookie last summer before landing on season-ending injured reserve before the start of the regular season, when he had a stress fracture in his foot.
On the other hand, Acker was drafted in the sixth round out of SMU, proving to be a quick study before starting in his first-ever NFL game over more experienced players like Johnson or Shareece Wright, who started 27 games for the Chargers the last two seasons.
Acker spent his rookie season on the shelf, but was still on the sidelines for every game and at the team's facillity regularly, participating in meetings and watching practices.
"I think that year off, knowing that I wanted to be on the field of course, it helped me a lot," said Acker. "It just put me in a position where I was comfortable with coming into the position. It wasn’t like it was my first time out there."
Acker allowed three catches in Monday's win, with one longer than four yards. Speedy receiver Charles Johnson made an 18-yard grab on Acker in the third quarter. Acker finished with four tackles while playing in all 56 defensive snaps. His three stops, according to PFF, tied him for the third-most among corners in Week 1.
In the preseason, Acker didn't miss tackle, while showing a knack for getting ball carriers down quickly.
"I feel like it’s an attitude thing at the end of the day," Acker said. "Some positions you put yourself in, if you attack, it makes it a cleaner tackle...It’s just like I’m filling my gap and filling my area, so when you look on the other side and see 10, nine other guys running that way, it’s not really that hard."
Of course, Acker isn't the only inexperienced contributor on defense. Young players like defensive tackle Quinton Dial, outside linebacker Aaron Lynch, nose tackle Ian Williams and rookie safety Jaquiski Tartt, and others, are stepping into key roles in new defensive coordinator Eric Mangini's attack-heavy system. The 49ers allowed 248 yards to the Vikings, the fourth fewest of any team in Week 1.
Acker's approach and preparation heading into 2015 have been pretty typical, according to one veteran.
"He pays attention to the details. He’s focused in meetings. I think he’s a business-like guy," linebacker Michael Wilhoite said. "I think that’s just kind how our defense and how this team is. I feel like we’re just a bunch of grind-it-out guys."
Next up on Acker's plate: the Steeler's dangerous offense and last season's receptions and yardage leader Antonio Brown. Brown got off to a quick start in Pittsburgh's season-opening loss to New England, catching nine passes for 133 yards with a touchdown.
"It seems like every week there’s a speed guy," said Acker, after going against Mike Wallace and Johnson, with Arizona's John Brown looming the next week. "I don’t think there’s a falloff with any team we’re going to play this year with having a speed receiver."
Chris Biderman is the Editor-in-Chief of Niners Digest and covers the 49ers from their headquarters in Santa Clara. Chris has been writing about the team since the spring of 2013. The Ohio State alum received his Journalism degree in 2011 and has been working in sports media since 2008. Chris, a Santa Rosa, Calif. native, is also a contributor to the Associated Press covering sports throughout the Bay Area. You can follow Chris on Twitter here.
E-mail Niners Digest: NinersDigest@gmail.com