Since becoming a full-time starter in 2011, 49ers guard Zane Beadles has made 96 straight regular-season starts and missed seven plays.
In other words, his second-string role this summer has been a bit foreign.
Still, Beadles, 30, a nine-year veteran coming off an impressive season, understands how this works.
“The moment you enter this league, they’re looking for someone to replace you,” Beadles said. “You have to understand that and have that mindset. This year, is no different and probably more so with the new regime.”
Last year, Beadles impressed the old regime, which signed him to a three-year, $9.75 million deal and saw him flash stunning versatility. Due to a rash of late-season injuries, Beadles spent time at tackle, a position he hadn’t played since 2010, and center, a position he’s never played at any level before 2016.
In training camp, however, Beadles has spent time watching Brandon Fusco, a free-agent signee, and Joshua Garnett, a 2016 first-round pick, start at guard. Beadles has returned to the first-string the past two practices because Garnett has a knee injury.
His insertion into the starting lineup could be coming at an opportune time: Beadles is more comfortable with the outside-zone blocking scheme that’s a staple of head coach Kyle Shananhan’s offense.
“Last year, it was a different challenge going out there and seeing what you can do at different positions and this is the same way,” Beadles said. “It’s taken some time, a lot of effort and a lot of work, but I think it’s coming together.”
Injury report: Garnett is expected to miss at least four weeks with a knee injury that head coach Kyle Shanahan has said will require minor surgery. Garnett attended practice with a sleeve on his left leg and had a long conversation with his college coach, Stanford’s David Shaw, who brought his staff to a practice in the spring.
Rookie tight end George Kittle (hamstring) returned to practice and took first-team snaps, while defensive tackle DeForest Buckner also returned after he was sidelined with an ankle injury.
Cornerback Rashard Robinson didn’t finish practice because of a shoulder injury that didn’t appear serious.
Roster move: The 49ers officially placed linebacker Malcolm Smith on injured reserve and filled his roster spot by signing Austin Calitro, an undrafted rookie linebacker from Villanova. Calitro was waived by the Jets on May 15 after a 10-day stint with the team.
Smith sustained a torn pectoral muscle in practice Saturday.
Eric Branch is a San Francisco Chronicle staff writer. Email: EBranch@sfchronicle.com Twitter: @Eric_Branch