SANTA CLARA, Calif. -- Frank Gore doesn't see turning 30 as a bad thing, even if it's the age when most NFL running backs start to decline.
If anything, the San Francisco 49ers' career rushing leader has embraced the milestone and sees it as another means of motivation.
"I love it," Gore said Thursday outside of the 49ers' locker room.
"I feel like every year it's something with me. I have to overcome everything, every year. Now that I'm 30 I just have to keep working and training hard."
Not that Gore has ever needed extra incentive.
Whether it was being bypassed in the 2005 draft when he was the sixth running back selected or the string of injuries he's endured and overcome since then, Gore has always felt the need to prove people wrong.
The 49ers clearly know Gore's value and have limited his participation in the off-season workouts, including this week's three-day minicamp.
San Francisco hopes the time off will help keep Gore fresher for the regular season. He's topped 1,000 yards in six of the past seven years, but he's also had a tendency to wear down late in the season.
Since the end of the 2009 season, Gore has failed to record a 100-yard game in the months of November and December. He rebounded to top that mark twice in the playoffs last season, including in the 49ers' Super Bowl loss to Baltimore when Gore ran for 110 yards and a touchdown.
That wasn't enough to silence the critics. And when Gore turned 30 on May 14, the doubts seemed to increase.
Even his spot on a recently released list of the top 100 players in the NFL didn't sit well with the ninth-year veteran. Gore was No. 32.
"They said he's turning 30 and he might not have (any) more left," Gore said. "I like that type of stuff. Whenever (the 49ers) let me get on the field, I'm going to go hard and prove everybody wrong again."
Just when Gore will be on the field is the question.
While he's done some light individual work, the 49ers have not let him take part in any on-field practices. He was a spectator at practice Thursday and likely won't put on pads until San Francisco opens training camp in July.
That led to speculation that Gore might be nursing an injury. But when questioned about it on Thursday, Gore was as elusive as he has been on the field.
"I'm cool, I'm good," he said. "I'm just listening to (head trainer Jeff Ferguson). He told me he didn't want me doing anything right now, and I'm listening. I'm just getting my body back. I want to be fresh whenever I get back on the field."
Keeping Gore fresh is critical considering the health of some of San Francisco's other running backs.
Kendall Hunter, the top backup behind Gore, is still mending from a torn Achilles tendon he suffered last season. Rookie Marcus Lattimore, one of the team's two fourth-round draft picks, is also trying to come back after an injury-filled college career that included a career-threatening right knee injury in 2012.
Gore and Lattimore have formed a kinship of sorts because of their similar histories. Gore suffered serious injuries to both knees while in college before rebounding to become a four-time Pro Bowl running back for the 49ers.
"He's a good kid," Gore said of Lattimore. "I went through the same thing, being one of the best backs at the school and getting drafted late in the rounds and you don't know if you could get back to (being) you. I'm pulling for him."
Notes: First-round draft pick Eric Reid was held out of practice with an unspecified minor injury, according to coach Jim Harbaugh. ... Wide receiver Brandon Carswell, who was signed on Wednesday, suffered a torn ACL. ... Anquan Boldin, the 49ers' prized off-season acquisition, was on the field but did not take part in the full-team scrimmage portion of practice.