The San Francisco 49ers’ extremely deep backfield quickly thinned out when running backs Christian McCaffrey and Jordan Mason were sidelined with injuries during the team’s Week 13 loss to the Buffalo Bills.

McCaffrey is already on injured reserve due to a PCL injury in his knee, and Mason is expected to end up there with a high ankle sprain. That leaves rookie running back Isaac Guerendo at the top of the depth chart with only unproven players behind him.

It’s obvious that Guerendo will play the lion’s share of the snaps. If he does, expect RB Patrick Taylor to serve as the backup for now. He was with the team throughout the offseason and played in the team’s first eight games of the regular season. In those contests, he primarily contributed on special teams, but also had seven carries for 25 yards and one reception for 12 yards.

His familiarity with the offense should make him head coach Kyle Shanahan’s trusted No. 2 RB in Sunday’s showdown against the Chicago Bears.

Recently signed RB Israel Abanikanda will serve as the No. 3 RB behind Taylor. Shanahan said Wednesday he knew Abanikanda after scouting him in the 2023 draft.

“I liked him coming out of college,” Shanahan said. “I didn’t study him much in the NFL, but he was a guy I had a good experience of in college and liked. And I know our scouting department thought he was the best available out there and stuff like that. That’s why, given our situation, I’m particularly happy to have him here.”

While Shanahan liked him in the draft, that doesn’t mean he’ll automatically take on a big role. The 49ers claimed him off waivers on Tuesday, meaning he only played three practices with the team. His lack of familiarity with the offense could limit him early and relegate him to a backup role even if Taylor takes on a larger workload.