The 49ers downgraded defensive end Dee Ford from questionable to out on Saturday for the game against the New York Jets due to a neck condition.
The 49ers also promoted center Hroniss Grasu from the practice squad to be available for the team's Week 2 game.
Coach Kyle Shanahan said Friday that Ford experienced neck spasms and was held out of practice on Thursday.
"We’re just trying to play it slow here and see how it goes for the next two days," Shanahan said.
Kerry Hyder, who registered one of the 49ers' two sacks against the Arizona Cardinals' Kyler Murray in Week 1, likely will fill in as the team's top edge rusher opposite Nick Bosa.
The 49ers expect Ben Garland to be available for Sunday's game, but the team also wants Grasu in uniform as an insurance policy.
Garland opened training camp as the team's starting center, but he was sidelined during the second padded practice this summer due to a high-ankle sprain.
The 49ers signed Grasu on Aug. 20, and he ended up as the team's starter in the season opener against the Arizona Cardinals.
The team's starting center, Weston Richburg, is out for at least the first six games of the regular season while on the physically unable to perform list while he continues to rehab from a knee injury that cut short his 2019 season.
Garland started the 49ers' final three games of last season and all three postseason games while Richburg was sidelined.
This season, due to the COVID-19 pandemic, teams are allowed to promote up to two players from the practice squad to the active roster on a weekly basis without being required to cut anyone to create roster space.