The 49ers promoted rookie offensive lineman Darrell Williams from the practice squad to the active roster Saturday and released veteran tackle Bryce Harris, whom they signed on Wednesday.
That means Williams essentially won a three-day competition with Harris and will serve as the so-called swing tackle in Sunday’s game. He’ll back up both Trent Brown at left tackle as well as the right tackle, which will be either Zane Beadles or Erik Magnuson.
The 49ers did not use any of their draft picks on offensive linemen. Williams (6-foot-5, 315 pounds) went undrafted out of Western Kentucky and played well during the offseason and preseason and landed on San Francisco’s practice squad. Magnuson went undrafted out of Michigan and made the team’s initial 53-man roster.
The 49ers also placed receiver Pierre Garcon (neck) on injured reserve Saturday while removing defensive end Ronald Blair (hand) from injured reserve.
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All NFL teams must deactivate seven players for each game. The 49ers have six who already have been ruled out: tackle Garry Gilliam (knee), defensive tackle D.J. Jones (knee), defensive end Aaron Lynch (calf), tackle Joe Staley (eye), defensive end Solomon Thomas (knee) and cornerback K’Waun Williams (quadriceps).
On Monday, Kyle Shanahan said that Gilliam would go on injured reserve with what was believed at the time to be an ACL tear. Subsequent tests, however, showed the injury was not as severe as initially feared. The team is hoping he’ll be able to play again this season.