Why the 49ers Don’t Use Christian McCaffrey and Brian Robinson Jr. Together

Christian McCaffrey and Brian Robinson Jr. being on the field at the same time hasn't occurred yet for the 49ers.

Nov 2, 2025; East Rutherford, New Jersey, USA; San Francisco 49ers head coach Kyle Shanahan looks on from the sidelines against the New York Giants during the first half at MetLife Stadium. Mandatory Credit: Robert Deutsch-Imagn Images | Robert Deutsch-Imagn Images

One interesting personnel grouping that the San Francisco 49ers could utilize is Christian McCaffrey and Brian Robinson Jr. on the field at the same time. It would give the 49ers a new dynamic offensively.

Maybe they go in shotgun with McCaffrey and Robinson in a split formation. Unfortunately, I wouldn’t hold my breath on seeing those two together on the field. Kyle Shanahan revealed on Wednesday why the 49ers don’t simultaneously play McCaffrey and Robinson. 

Opportunities to play both running backs aren't there

San Francisco 49ers running back Christian McCaffrey (23) scores a touchdown during a week 9 game between New York Giants and San Francisco 49ers at MetLife Stadium on Sunday, Nov. 2, 2025. | Julian Leshay Guadalupe/NorthJersey.com / USA TODAY NETWORK via Imagn Images

“It depends how the defense plays it,” Shanahan said. “I mean, just them being on to same field, I’m thinking of the advantage of when you have two running backs and they go nickel all the time, that to me doesn't mean you necessarily have two running backs. That means you have three receivers because now they're going against all corners instead of linebackers and safeties. Which can give you advantage to run if one of your running backs wants to play fullback. 

“So, we could do that, but just putting two runners out there because one's good in the pass game, if they want to stay base and stuff and play us like we have a fullback in there, then that could be an advantage because now he's out there having the advantage of a fullback being in the game, which means you're going against the linebacker or safety. So, it really depends on how the defense would play it and they don't tend to play us that way.”

Nov 9, 2025; Santa Clara, California, USA; San Francisco 49ers running back Brian Robinson Jr. (3) celebrates after a play during the third quarter against the Los Angeles Rams at Levi's Stadium. Mandatory Credit: Cary Edmondson-Imagn Images | Cary Edmondson-Imagn Images

Trotting out McCaffrey and Robinson together isn’t as simple as it’s made out to be. That’s what Shanahan is alluding to. They can’t just run both of them out there just for fun.

There has to be a meaningful purpose that makes them believe it’ll succeed. Shanahan is amazing with drawing up formations and plays that can gash defenses.

If he believes that McCaffrey and Robinson aren’t a personnel grouping that isn’t easy to make work, then his words should be taken at face value. It’s not like he doesn’t want to run it.

As he said, defenses won’t make it a walk in the park for them to do it. Robinson not being that good of a pass catcher also complicates it. Otherwise, it just becomes a predictable formation.

But who knows?

Maybe in one game soon, the 49ers will utilize both of them. 

Follow Jose on X (Twitter) @JS3sanchez_to interact with him on the 49ers.

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