Projecting how Rams, 49ers will adjust to new defensive schemes

Two NFC West rivals, the Los Angeles Rams and San Francisco 49ers, will play under new head coaches next season. They'll have new defensive coordinators, too, who will bring with them new defensive schemes.

For the Rams, that means converting from the 4-3 the team played under Gregg Williams to Wade Phillips' 3-4.

The 49ers will move in the other direction, with the team expected to replace its 3-4 with a 4-3 scheme similar to what Gus Bradley ran with the Jacksonville Jaguars. (The 49ers are expected to hire Robert Saleh, who was Bradley's linebackers coach, as their next defensive coordinator.)

Scheme changes don't always go smoothly. How do the Rams and 49ers' current personnel fit?

Rams

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Phillips' 3-4 is malleable, and there is reason to believe it won't look all that different from the Rams' previous 4-3.

With the Denver Broncos over the past two seasons, Phillips sent just three pass-rushers at the quarterback on only 41 snaps, according to ESPN's Alden Gonzalez. Only four teams did it less frequently. He sent five pass-rushers fairly regularly, but not much more than Williams' blitz-heavy Rams did.

Aaron Donald, arguably the NFL's best penetrating interior rusher, should remain in a 3-technique role, lining up on the outside shoulder of a guard. Michael Brockers is expected to play nose tackle, and William Hayes could have the inside track to start at the other defensive end spot.

This means 2013 Defensive Player of the Year Robert Quinn will likely transition from defensive end to outside linebacker. Quinn is heavier than Von Miller, who flourished under Phillips in Denver, but the two have comparable athleticism.

The Rams played primarily in the nickel last season, so they're used to playing with only two non-rushing linebackers on the field. Alec Ogletree shouldn't have too much difficulty adjusting from 4-3 middle linebacker to 3-4 inside linebacker (though there are lingering concerns about just how good he really is), but there are major question marks about where converted safety-to-weakside-linebacker Mark Barron will fit.

Barron certainly doesn't have the pass-rushing chops to stick at outside linebacker in a 3-4, nor does he likely have the bulk to kick inside and line up next to Ogletree.

Absent a move back to strong safety or the further diminishing of his role as a nickel-only player, it's hard to see where Barron fits in Phillips' scheme. Despite signing a five-year, $45-million contract last March, he may be the odd man out.

The Rams' biggest need may be at outside linebacker opposite Quinn. That could be the team's target in the draft, but it's worth noting the Rams don't own a first-round pick.

At 69 years old, this isn't Phillips' first time converting a 4-3 scheme to a 3-4 (nor is it his second, or third). He should have the experience to get the most from the Rams' talented defenders, and there's no reason to believe the unit can't be one of the best in the NFL in short order.

49ers

(Photo courtesy: Getty Images)

The 49ers' defense isn't completely bereft of talent, but there are few playmakers to be found here. That should make the team's task of converting schemes much harder than that of the Rams.

Complicating matters is the fact that the 49ers' last two early first-round picks, DeForest Buckner and Arik Armstead, each stand 6-foot-7 and are prototypical 3-4 players.

The Seattle Seahawks' 4-3, which Bradley brought to the Jaguars and which Saleh is expected to run in San Francisco, is closer to a 3-4 than many other 4-3 schemes because of the way it utilizes the strong-side linebacker - termed the OTTO - on the line of scrimmage next to a run-stuffing defensive end who bears a resemblance to a 3-4 defensive end.

Armstead is bigger than a typical 4-3 defensive end, but he has edge-rushing skills and could potentially play there in the new scheme. That would allow the 49ers to line up Buckner, their best interior pass-rusher, next to Armstead and attempt to overwhelm one side of their opponent's offensive line.

The weak-side defensive end in Bradley's scheme, the LEO, is the rough equivalent of a 3-4 outside linebacker. The problem for the 49ers is they don't really have a perfect fit for that spot. Tank Carradine and Eli Harold are candidates.

Then there's the matter of who plays at the other defensive tackle spot. Your guess is as good as anyone's.

Assuming his recovery from an Achilles tear is on track, NaVorro Bowman is the obvious choice to play MIKE linebacker. He should be the key cog in this defense - its Luke Kuechly.

Who lines up beside Bowman at linebacker is much less clear. The 49ers have some options, but not many good ones.

Ultimately, how the 49ers convert to a 4-3 this season might not matter. This team needs a substantial rebuild on defense, and, with few players under contract beyond 2017, this unit could look drastically different in 2018.