SANTA CLARA -- Eleven-year veteran Justin Smith sees an opportunity with the 49ers this season that does not come along very often.
The maniacal worker sets the tone for the 49ers in the weight room during the club's offseason program. Although he is not necessarily known as a vocal leader, Smith has also been stressing a verbal message.
"The mindset that I've been spreading a little bit to the guys is, you know, your team isn't always stacked forever," said Smith, a first-team All-Pro defensive lineman.
"With free agency (and) the way drafts are set up -- if you have successful seasons you get the lower end of the draft -- you have certain windows. You don't want to get into, 'Is this our window? Do we have two years, three years?' I wouldn't say that.
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"I know with some of the guys we have and with free agency, we're not going to be able to keep this team together forever. Even age-wise, the whole team won't be the same."
So Smith's message is to continue to do every bit of work to prepare for the upcoming season and have no regrets. Smith spoke on Thursday, the final day of the 49ers' three-day mandatory minicamp.
The 49ers dominant defense from a year ago returns intact, as the front office managed to retain cornerback Carlos Rogers, outside linebacker Ahmad Brooks and backup inside linebacker Larry Grant.
It gives the 49ers hope that the defense can be even better than a year ago when the club won 14 games and advanced to the NFC Championship, losing in overtime to the eventual Super Bowl-winning New York Giants.
San Francisco 49ers
"I don't think we have anybody on our defense right now that should be descending in their career," 49ers defensive coordinator Vic Fangio said. "We don't have anybody that's old enough that they shouldn't play as well as they did last year, or even better.
"And I think Justin's probably our oldest guy (32) and I would expect nothing but even the same or better performance from him moving forward. And I feel that way about all our guys."
Smith said he believes the 49ers' front office saw an opportunity with an already-talented roster to make key moves to keep the defense together while strengthening the offensive firepower.
"I think this year we feel (if we) put everything together and work the way we need to work, hopefully, we can accomplish our goal," Smith said. "Let's go out and try to hammer this thing home. That's our goal. And 31 other teams' goal, as well, so it'll be tough to achieve but we feel we have the team to do it."