SANTA CLARA, Calif. (AP) Jim Tomsula has been tested so many times already as a first-year NFL coach.

From surprising retirements by team stars to yet more legal run-ins for a franchise defined by them in recent years, Tomsula so far has plugged away admirably, gaining the trust and respect of his players in the process.

Whether he can win is the question everybody is eager to find out, and the 49ers will try to do so without Patrick Willis and Anthony Davis, Aldon Smith, Justin Smith and Chris Borland. And without Jim Harbaugh, who led the team to three straight NFC championship games before last season's dud.

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''The way that you prepare gives you an opportunity. The guys that we have in the locker room, I know what kind of guys we have in here,'' wideout Anquan Boldin said. ''Those are guys that are going to bust their butt, try to do things the right way as much as possible. Nobody's perfect. We're going to try to go out and try for perfection each day.''

Willis, Davis, Borland and Justin Smith retired, while Aldon Smith was released Aug. 7 after more legal trouble. Franchise rushing leader Frank Gore and former first-round pick offensive lineman Mike Iupati each departed in free agency.

Despite all the turnover, the 49ers are counting on the talent they still have to carry them back to respectability on the heels of an 8-8 season and the first time out of the playoffs in four years.

''It's been a long offseason. Obviously we didn't finish the season last year the way we wanted to,'' third-year safety Eric Reid said. ''We didn't make the playoffs. The bright side of it was the guys got to get away for a long time, seven months. Hopefully we're all healthy and ready to get back at it.''

Here are some things to watch for with San Francisco:

STRONG-ARMED KAEPERNICK: Kaepernick spent a good chunk of the offseason working with Kurt Warner and other quarterback gurus in Arizona, but through the preseason hardly looked polished as he struggled to build any momentum for an offense that will be scrutinized from Day 1.

Kaepernick and the first-team offense failed to score a touchdown on eight preseason possessions.

BOWMAN'S COMEBACK: Bulky brace or not on his surgically repaired left knee, NaVorro Bowman has shown immediately he is back to the defensive force he was before a devastating injury during the NFC championship at Seattle in January 2014.

He made three tackles in three snaps in his return during the second preseason game, then sacked Peyton Manning twice in a loss to the Broncos in the third exhibition contest.

''I'm satisfied with how much work I've put in, how far I've come, how fast I'm able to recover coverage-wise,'' Bowman said.

O-LINE QUESTIONS: This unit used to be a model of stability for San Francisco, and Joe Staley, Alex Boone and the others are determined to get back to that level. But the O-line is one of the biggest question marks - especially with young center Marcus Martin and two new faces on the right side in guard Jordan Devey and tackle Erik Pears.

Kaepernick took 52 sacks last season, second most in the league behind the 55 on Jacksonville's Blake Bortles, and the offense struggled with clock problems.

''I think everyone realizes the players we have lost and the players we have here are very capable of stepping in and being impact players for us,'' Kaepernick said.

AUSSIE ENTHUSIASM: Jarryd Hayne has a whole country cheering him back home in Australia, and the former rugby league star has quickly earned plenty of fans in the Bay Area, too.

He secured a spot on the 53-man roster with his stellar preseason and training camp.

''The odds of an American that grows up in this game playing in the National Football League ... it's astronomical,'' Tomsula said. ''Now you're talking about a guy that was not raised in this game and he's made it. It's a tremendous achievement. I think that's why everybody's so enamored with it. That true story, the American way, or the Australian way.''

DETERMINED DAVIS: Vernon Davis would rather forget last season and all the frustration with his health and a lesser role.

He is ready to return to top form for a contract year and bring his numbers back near where he had them with 13 touchdowns in 2009 and again in `13.

The 31-year-old Davis managed only 26 receptions for 245 yards and two TDs last year.

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