Kurtenbach: Christian McCaffrey and Brian Robinson Jr. in the same 49ers backfield? Don’t bet on it

You can want it. You can hope for it. But please, I’m begging you — don’t expect it.

The moment the 49ers traded for running back Brian Robinson Jr., the drumbeat started. From fans, from the media, from anyone with a fantasy football team, the call came for Niners head coach Kyle Shanahan to play Robinson and Christian McCaffrey on the field at the same time.

If I’ve heard it once, I’ve heard it a thousand times now. And it’s starting to give me a headache.

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The logic, as it goes, is that this two-headed monster would solve the 49ers’ wide receiver depth issues — just flex McCaffrey out to the slot. The argument is that it puts the team’s “best 11” on the field.

But this isn’t Madden, folks.

Pushing for a Robinson-McCaffrey backfield shows a fundamental misunderstanding of how Shanahan’s offense actually works and, more importantly, the specific skill sets of both players.

So why won’t it happen?

Let’s start with the simplest reason of all: the data.

In his 49ers career, Christian McCaffrey has taken 1,504 regular-season snaps.

Guess how many of those included another true running back (not fullback Kyle Juszczyk or receiver-in-disguise Deebo Samuel) on the field with him.

Fifteen.

That’s it. That’s less than 1 percent. And digging into those 15 snaps — 14 in 2023, one in 2022 — reveals precisely why a CMC-and-B-Rob backfield will remain fan fiction.

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Now, to be fair, 15 isn’t nothing. Shanahan has done it before and he could do it again — the plays are in the playbook.

And if he were ever going to dust them off, Week 1 against Seattle might be the time. Not because of the Niners’ receiver situation, but rather because the Seahawks’ defense presents the exact niche scenario where it makes a sliver of sense.

This funky, two-back personnel group was a gimmick package, used almost exclusively against gimmicky defenses that play with no deep safeties. Think aggressive red-zone situations and against chaos-agent defenses. There, Shanahan can basically go back to high school and run a veer option offense.

– He first used it in Week 18 of 2022 against the Cardinals on a slick red-zone play where McCaffrey’s sweep action pulled the defense with him, allowing Elijah Mitchell to score with a run the other way.
– He went back to it for four plays against Vikings defensive coordinator Brian Flores’ blitz-heavy Cover-0 scheme in 2023. One play resulted in a 35-yard touchdown for McCaffrey on a swing pass.
– The next week against Cincinnati, Shanahan tried it five more times. That game, it featured a botched option play that turned into an interception.
– Later that season, against Jacksonville, Shanahan used it for three snaps in a blowout, when he was trying, inexplicably, to force-feed McCaffrey the ball to extend his touchdown streak.

The schtick had run its course. Shanahan tried the two-running-back look two times after that. The last time we saw it, McCaffrey was basically a lead-blocking tight end for a Deebo reverse. Woof.

Which brings us to 2025.

Wouldn’t fate have it that the Seahawks led the NFC in Cover-0 snaps last season? (Seven percent of dropbacks.) If ever there was an opponent to tempt Shanahan, this is it.

The problem? Brian Robinson isn’t the right player to run the sets.

The Commanders tried moving Robinson around the formation last year, and it was hardly a success. He has decent hands, but he isn’t shifty enough for a defense to truly respect him as a receiving threat. There’s a reason 20 percent of his receiving yards last season came on one busted play where Tampa Bay simply forgot to cover him. It’s likely why Washington was willing to trade him for pennies on the dollar and eat some of his salary to do it.

Mitchell wasn’t a world-class receiver either, but at 25 pounds lighter, he possessed enough quickness to create the threat of a mismatch. That’s sometimes all you need. For the package to work, both backs have to be credible pass-catchers.

No, Robinson is much more like Jordan Mason — the thunder to McCaffrey’s lightning. And in their two-plus seasons together, Mason and McCaffrey never shared a single snap.

So why not just line up McCaffrey in the slot full-time?

Because doing so squanders his greatest asset: versatility that creates mismatches.

We should all know by now that Shanahan’s offense is built on finding a small advantage and exploiting it a hundred different ways. And McCaffrey, like prime Deebo before him, is the ultimate chess piece. Line him up in the backfield, and the defense has to use heavier personnel to respect the run. Once they do, Shanahan can motion McCaffrey out wide and suddenly a linebacker is stranded in coverage against him. It’s a guaranteed win.

The same truth works in reverse.

You can’t cover McCaffrey with a linebacker in the passing game, and you can’t tackle him with a defensive back in the run game.

But you know who can cover McCaffrey when he’s just a receiver? A cornerback.

(Watch back those three strange plays against the Jaguars in 2023 to see exactly what I mean.)

Playing McCaffrey as a straight-up receiver or using a two-running-back set where one back isn’t a receiving threat concedes that critical advantage before the snap. It fundamentally contradicts Shanahan’s core philosophy.

Perhaps desperate times call for desperate measures. But I’ll bet on the coach with a well-earned reputation for tactical stubbornness to stick with what he knows works, especially in Week 1.

But, hey, I bet the sets are fun in Madden.