Kyle Shanahan and the San Francisco 49ers got themselves back on track in Week 14 with a 38-13 victory over the Chicago Bears, but the injury bug that has plagued them all season long came back to rear its ugly head again, as the team lost their new starting running back Isaac Guerendo to a foot injury in this game.

With Christian McCaffrey and Jordan Mason both landing on injured reserve after the team’s Week 13 loss to the Buffalo Bills, that thrust Guerendo, a fourth-round rookie, into the starting job. And in his first start, Guerendo turned in a strong effort, as he racked up 128 total yards and two touchdowns.

The problem was that Guerendo became the latest San Francisco player to suffer an injury, as he was forced out of this game early. On Monday, Shanahan revealed that Guerendo had suffered a foot sprain that could ultimately hold him out of their upcoming Thursday Night Football contest against the Los Angeles Rams.

Per Adam Schefter of ESPN, “49ers HC Kyle Shanahan said RB Isaac Guerendo has a foot sprain and the team will ‘evaluate him over the next few days, to see if he’ll have a shot’ to play Thursday night versus the Rams.”

49ers HC Kyle Shanahan said RB Isaac Guerendo has a foot sprain and the team will “evaluate him over the next few days, to see if he’ll have a shot” to play Thursday night versus the Rams.

— Adam Schefter (@AdamSchefter) December 9, 2024 Considering how well Guerendo played against the Bears, and how the Niners are already without their top two running backs, losing him would be catastrophic. But with a quick turnaround in Week 15, it makes Guerendo’s chances of getting himself healthy for this pivotal clash become much smaller.

After Guerendo was forced out of the game, San Fran turned to Patrick Taylor Jr. at running back, and he would likely get the start if Guerendo cannot play against the Rams. The 49ers also have Ke’Shawn Vaughn and Israel Abanikanda available to round out their running back depth chart.

The Niners will be hoping to have Guerendo at their disposal against the Rams, as they desperately need a win against their division rival if they intend on keeping their miniscule playoff hopes alive. Guerendo will work on getting himself healthy, but time is not on his side thanks to San Fran having a short week on their hands.