49ers RB depth chart: Isaac Guerendo, Patrick Taylor Jr. lead options after Christian McCaffrey, Jordan Mason injuries

The 49ers are being forced to go deep into their running back room just six weeks into the season.

San Francisco was dealt a tough hand when 2023 AP Offensive Player of the Year Christian McCaffrey missed the season-opener with an Achilles injury. He was placed on injured reserve , paving the way for backup running back Jordan Mason to fill in as an interim starter.

Mason played that role to perfection, racking up 536 yards and three touchdowns on a league-high 105 carries over the first five games. His rushing yardage total was second to Ravens star running back Derrick Henry (572 yards) going into the 49ers' Week 6 matchup with the Seahawks.

Mason suffered a shoulder injury in the second quarter of San Francisco's "Thursday Night Football" game in Week 6. He returned for one play but couldn't last longer, as he was repeatedly shown on the sideline working out his arm and talking to trainers. That forced the 49ers to go a step further on the depth chart, calling on a rookie to handle ball-carrying duties.

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49ers RB depth chart

1. Isaac Guerendo

At RB3 for San Francisco is Guerendo, a rookie drafted in the fourth round back in April.

Guerendo played at Wisconsin and Louisville throughout his college career. His best season came in 2023 with the Cardinals, finishing with 810 rushing yards and 11 touchdowns.

Guerendo came into "Thursday Night Football" with 12 carries for 41 rushing yards. He took on the bulk of the initial carries in Mason's absence and will likely become the 49ers' starter if Mason is forced to miss any time.

2. Patrick Taylor Jr.

The final RB on the 49ers' roster is Taylor Jr., who spent the past three seasons with the Packers.

Taylor Jr. had a career-high 141 rushing yards last season in a packed Green Bay RB room. He has just one touchdown in his NFL career so far, which came in 2021, but he profiles more as a receiving back, as he had 11 receptions in his limited field time last season.

Taylor handled a couple of carries once Mason went down on "Thursday Night Football" but he was mostly in for passing downs, seeing a few targets.