Niners add some depth in the backfield and on defensive line

Established starters are in place at running back and defensive line but the 49ers made shrewd moves Wednesday for depth at those critical positions.

Shortly after the 49ers announced the signing of former New York Giants running back Wayne Gallman, ex-Raiders’ pass-rusher Arden Key agreed to a one-year deal, NFL Network reported.

Gallman offers an experienced, versatile option behind the 49ers’ top two backs, Raheem Mostert and Jeff Wilson Jr. Others in the running back corps are JaMycal Hasty and Austin Walter.

Gallman (6-foot, 216 pounds) was the Giants’ leading rusher last season after Saquon Barkley sustained a Week 2 knee injury. Gallman ran for 682 yards (4.6-yards per carry, six touchdowns) and had 21 receptions for 114 yards.

In his Giants’ tenure, he totaled 1,444 rushing yards (338 carries, nine touchdowns) and 498 receiving yards (80 catches, two touchdowns) with the Giants (53 games, 14 starts).

The 49ers make sense for Key in that they’ll need edgerushing help as Nick Bosa (knee) and possibly Dee Ford (back) return from injuries that wiped out almost their entire 2020 seasons.

Key totaled only three sacks through 37 games with the Raiders, who selected him in the third round of the 2018 draft out of LSU.