Connor Colby

The 49ers have an established track record for mid-round running back investments during the Kyle Shanahan-John Lynch era. Unfortunately for the team, the moves have a high bust rate.

San Francisco drafted Joe Williams in the 2017 fourth round, trading up for the Utah back. Williams did not play an NFL snap. The team tried again by drafting Trey Sermon in the 2021 third round. Sixth-rounder Elijah Mitchell outplayed Sermon, who saw minimal San Francisco action before being waived in 2022. The team misfired once again in Round 3, with its Tyrion Davis-Price pick (2022) yielding little before a 2023 separation.

The 2024 draft brought another swing, with Isaac Guerendo joining the team in Round 4. Shortly before Guerendo’s second season, however, the 49ers traded for Brian Robinson to serve as Christian McCaffrey‘s backup. Robinson moved on in free agency (to the Falcons) in March, but the 49ers went back to the draft well again by choosing Indiana’s Kaelon Black in Round 3 despite the Indiana product not being invited to the Combine.

Black joins 2025 fifth-rounder Jordan James as McCaffrey backup options alongside Guerendo, but the third-year player may be on the outside looking in. Guerendo is now a long shot to make San Francisco’s 53-man roster this summer, The Athletic’s Vic Tafur writes. The 49ers are expected to feature an RB2 competition between James and Black, Tafur adds.

Guerendo, who clocked a 4.33-second 40-yard dash at the 2024 Combine, averaged 5.0 yards per carry as a rookie (84/420) and scored four touchdowns. McCaffrey missed most of that season but returned to his full workload in 2025, with Robinson serving as the clear backup. Guerendo, who played alongside Mitchell in 2024, went from 227 offensive snaps as a rookie to zero last season. He could find himself elsewhere via waivers or perhaps in a low-level trade, though the 49ers could perhaps save a practice squad spot come August.

While McCaffrey’s backup — a rather important position considering the All-Pro’s injury history — has yet to be decided, the team will be looking for a Week 1 left guard starter as well. Spencer Burford and Ben Bartch defected in free agency (to the Raiders and Lions, respectively), leaving a hole opposite Dominick Puni. The team signed Robert Jones and will put him in a competition with second-year blocker Connor Colby and rookie fourth-rounder Carver Willis, Tafur adds.

Jones, who missed all of last season with a broken bone in his neck, comes over from the Cowboys but last made contributions with the Dolphins. The four-year Miami blocker, 27, started 30 games for the Dolphins — including 17 in 2024. Jones only commanded a one-year, $3.75MM Dallas deal and signed for $1.75MM ($1.64MM guaranteed) with the 49ers.

The 49ers initially turned to Colby after Bartch’s Week 2 injury last season but ended up going with Burford as a nine-game starter. Burford joined the Raiders on a one-year, $3.26MM contract. Willis played left tackle with Washington as a senior and was Kansas State’s starting right tackle in 2024. The 49ers, who signed Vederian Lowe as a swing tackle this offseason, are moving Willis to guard.

Although Jones has by far the most experience here, Colby — an Iowa product drafted in last year’s seventh round — will be given “every opportunity” to beat him out, per Tafur. Pro Football Focus ranked Colby 66th among guards as a rookie, but the 49ers look to remain bullish on his chances. Two years remain on Puni’s rookie deal, keeping the team’s RG situation stable for the foreseeable future.