49ers RB room: Who stays, who goes?

Will there be a new veteran playing alongside the rookies from this past season?

We’re expecting to see multiple changes on offense and defense for the 49ers this offseason. And while the quarterback will receive much of the attention, running back could see a makeover, too.

What to make of the rookies

Elijah Mitchell and Trey Sermon enter their second years with the team. Mitchell missed a good chunk of training camp with an injury but still made more of an impression on the coaching staff than Sermon, who the 49ers traded up to select.

I’ve gone back and forth on just how valuable Mitchell is. He has speed and is a no-nonsense runner who runs through arm tackles. But there’s still something left to be desired. Mitchell’s vision ran hot and cold, and it felt like he left some meat on the bone this past season. And while he bounced off opposing tacklers, I never came away thinking Mitchell ran with a lot of power.

According to Sports Info Solutions, Mitchell averaged 6.1 yards per carry when he rushed outside of the tackles compared to just 2.6 yards when he ran between the guards. That’s pretty telling. Mitchell has the trust of Kyle Shanahan, and his volume down the stretch evidenced that.

Sermon came in with high expectations but disappointing in Year 1. That doesn’t mean he’s a bust. Sermon learned the hard way that if you’re not decisive in your decision-making as a runner, then you cannot play.

The Niners could use either player more as a receiver out of the backfield. During training camp, it was Mitchell who looked as though he’d be a mismatch. He was beating the second, and third-team linebackers left and right. Yet, we rarely saw him used as a receiver.

That could be the role Sermon takes over, especially if he learns how to pass protect. Ideally, Mitchell would be the “do-it-all” runner, but, at the same time, you don’t want to overload Mitchell after he was banged up this past season.

A new veteran?

Jeff Wilson Jr. and Raheem Mostert are unrestricted free agents. Wilson looked a shell of himself after returning from an ankle and a knee injury. He’s still relatively young, but Wilson didn’t have the same burst when he played this season. Wilson averaged 3.7 yards per carry and only 3.2 on rushes outside of the tackle. Furthermore, Wilson’s broken tackle rate was 3.8, compared to Mitchell’s 9.7.

Mostert will turn 30 in April and is coming off a season-ending injury. There’s speed, and then there’s Mostert. He couldn’t follow up an impressive 2019 season as Mostert missed half the season in 2020. He then lasted two carries this past season.

I think the world of Mostert. To me, he’s one of the five best running backs in the NFL when healthy. He gets downhill, outruns an angle, and it’s off to the races. Mostert looked like he was going to run for 200 yards against the Lions in Week 1. On 69 carries outside of the tackle in 2019-20, Mostert averaged 6.9 yards per carry. He made up for insufficient blocking upfront.

The Niners should bring Mostert back on a cheap contract. He’s the best running back on the team. Mostert should be affordable given his injury history, and despite Mitchell’s success, I’m not taking Mostert off the field for the rookie.

If they look to go in a different direction, the list of free-agent running backs won’t excite you. Would Seattle’s Rasaad Penny interest the team? Chase Edmonds from Arizona could serve as an inside runner. I say this half-jokingly, but Matt Bredia and Jerick McKinnon are available.

This season, Mitchell missed enough starts that the team should look to bring in a veteran, preferably a pass-catching back who can excel inside the tackles. If Mostert isn’t the answer, I’d look to go the direction of the draft once again.