The 49ers left a 53-man roster spot open after placing CMC on IR

MINNEAPOLIS – The 49ers did not make a roster move Saturday to fill Christian McCaffrey's 53-man roster spot.

San Francisco will take three active running backs against the Minnesota Vikings on Sunday, led by starter Jordan Mason.

The 49ers placed McCaffrey on injured reserve with calf tightness and Achilles tendinitis, ruling him out for the next four games. San Francisco now has an open 53-man roster spot.

The 49ers again promoted veteran safety Tracy Walker III from the practice squad with Talanoa Hufanga not expected to play.

Hufanga is listed as questionable to play as he remains in condition following season-ending surgery on his torn right ACL in November.

George Odum is expected to remain with J'Air Brown as the starting safety until Hufanga is cleared to return to action.

The 49ers will again lean heavily on Mason as the lead back. He gained a career-high 147 yards and a touchdown on 28 rushing attempts in the 49ers' 32-19 Week 1 win over the New York Jets.

Wide receiver DeBo Samuel could also get some carries out of the backfield or jet sweep. He had 23 yards and a touchdown on eight rushes against the Jets.

Coach Kyle Shanahan said he wouldn't hesitate to call up rookie Isaac Guerredo, a fourth-round draft pick from Louisville. He played three snaps from scrimmage in Week 1 but had no carries.

Guerredo missed much of training camp with a hamstring injury but looked impressive in the 49ers' final preseason game against the Las Vegas Raiders.

“Even at that moment the game didn't seem too big for him,” Shanahan said Friday. “And he's been that way ever since.”

Patrick Taylor, who played his first three seasons with the Green Bay Packers, will serve as the team's No. 3 running back.

Download and follow the 49ers Talk Podcast