The changing to a guard is official for Anthony Davis.

After taking sporadic snaps at the position recently, Davis spent the majority of his time as the 49ers’ first-team right guard in practice Tuesday.

After the session was over, the former right tackle declared it was his new position. Davis replaced guard Andrew Tiller after he’d spent most of the summer as the second-team right tackle.

“It’s exciting to finally be able to jell with those (first-team) guys and just know what group is going to go out there,” Davis said. “We can grow together as a unit.”

Actually, the first-team offensive line isn’t set, given the developments at left guard. On Tuesday, rookie Joshua Garnett said he’s been “splitting the reps” with Zane Beadles in practice this week. Garnett, the No. 28 overall pick, spent training camp with the second-team offensive line.

If Davis and Garnett are Week 1 starters, they would join left tackle Joe Staley as first-round picks on the offensive line. They would be joined by center Daniel Kilgore and right tackle Trent Brown, a 2015 seventh-round pick whose promising play prompted Davis’ position switch.

“It’s exciting because we can do a lot better than we did (last year),” Davis said. “…We’re just getting started, I feel like.”

Davis, of course, wasn’t with the team in 2015 when the 49ers allowed the second-most sacks in the NFL. But after taking a year off, he reported to training camp at 332 pounds, about 35 fewer pounds than he weighed in 2014.

“I feel like that played a big role — coming in ready to play football,” Davis said.

Davis, 26, cautioned that he’s in work-in-progress mode after not playing guard since his freshman season at Rutgers in 2009. As part of his education, he plans to study Arizona guard Mike Iupati, his Pro Bowl teammate during his first five seasons in the NFL.

“It will take time getting used to it,” Davis said. “I’ll watch a lot on Mike Iupati, probably, to figure it out. Mike will help me out. I’ll call him.”

Receiver signed: The 49ers addressed their depleted wide-receiver corps by signing Ryan Whalen, a 2011 sixth-round pick from Stanford. Whalen had 11 catches for 80 yards with the Bengals from 2011-13.

Whalen, 27, hasn’t played in a regular-season game since the 2013 season. The Alamo native was released by the Vikings during final roster cuts last year.

Niners wide receiver Eric Rogers suffered an ACL tear early in training camp, and DeAndre Smelter remains sidelined with a hamstring injury that has kept him out of the first two preseason games.

Eric Branch is a San Francisco Chronicle staff writer.