Two days ago, 49ers offensive lineman Anthony Davis was the team’s starting right guard and the backup at both tackle positions.

Now, he might be solely a backup player.

Davis, 26, has decided to remain with the 49ers and will play only the tackle positions, Jennifer Chan of NinersNation.com reported on Sunday. Davis was moved into the starting lineup at right guard ahead of Andrew Tiller two weeks ago. He did not participate in practice on Saturday, and sources told CSNBayArea.com that he contemplated retirement. Davis was back at practice on Sunday, a source said.

The 49ers open the regular season Monday night against the Los Angeles Rams at Levi’s Stadium. Tiller would likely regain his starting job if Davis is no longer in the mix at right guard. The right guard will match up mostly against Rams standout defensive tackle Aaron Donald, who recorded 11 sacks last season, matching Cincinnati's Geno Atkins for most in the NFL among defensive tackles.

Tiller started seven games last season and played well after being promoted from the practice squad in mid-October.

On Friday, 49ers coach Chip Kelly spoke about Davis and starting right tackle Trent Brown forming a strong combination on the right side of the offensive line.

“That group of guys, they are doing a tremendous job and the depth that we have in that O-line room is phenomenal,” Kelly said. “It’s the deepest I’ve ever been around. Everybody in that room is a good football player and the starting five right now are doing a tremendous job.

“You’re really starting to see how Trent and (Davis), Daniel (Kilgore), Zane (Beadles), and Joe (Staley) kind of all work together, how they are kind of gelling as a group. It’s been fun to watch and there’s only going to be continued improvement throughout the year, especially with AD and Trent being new together on the right side. It’s just going to keep getting better from here on out.”

On Aug. 18, Davis said he approached 49ers offensive line coach Pat Flaherty and volunteered to move to guard if it would help the team.

“I’m an athlete,” Davis said. “I can play anywhere on the line, and right now we want the best five on the field. And Trent is not going to play guard. He’s a giant man. I know I can adapt to guard, so I feel like that can help us.”

Davis played right tackle for all of his first 81 regular season and playoff games in his first five seasons with the 49ers.