The San Francisco 49ers are looking to the free agent market after backup running back Elijah Mitchell suffered an adductor strain during training camp. With Mitchell expected to be sidelined another week, the 49ers worked out free agents Duke Johnson, Jeremy McNichols, Brian Hill and Jason Huntley on Monday, per Field Yates of ESPN.

All-Pro Christian McCaffrey is the undisputed starter in San Francisco, but Mitchell, 25, had been the team's lead back during his rookie year in 2021 and even played an important role after the trade for McCaffrey this past season.

Even if Mitchell didn't get banged up at 49ers training camp, it still makes sense for the team to seek added depth at the running back position.

For all McCaffrey's talents- he's the best two-way threat at the position- he has missed extended periods of time in two seasons of his career.

Meanwhile, Mitchell, who powered his way to a 963-yard rushing season two years ago, has missed time in each of his first two seasons with a slew of injuries.

In Duke Johnson, the 49ers are eyeing a veteran running back who excels as a pass-catcher out of the backfield.

The likes of McNichols and Hill each have experience as key backups for teams on depth charts in the past, while the 25-year-old Huntley represents a sort of upside halfback.

There's no guarantee that any of these veterans will put pen to paper for the 49ers. But the team clearly isn't taking any chances with two injury-prone backs atop their depth chart heading into the 2023 season.