Should the 49ers Stay in a 3-4? Or Switch to a 4-3? “Endless Possibilities”

Niners Live makes an in-depth assessment of the fundamental differences and advantages/disadvantages of a 3-4/4-3, as well as endless possibilities. (Operation Front Seven).



3/4 breakdown at a glance:

The San Francisco 49ers currently run a 3-4 (3 defensive lineman and four linebackers, a two gap system in which each man is responsible for two gaps) as their base defense and have even had success at times, so continuing to do so would make sense based upon past outcomes. With the current roster, the 49ers have some flexibility with personnel to maximize the effectiveness of the 3-4, such as it stands: DeForest Buckner, Arik Armstead, Ronald Blair, Glenn Dorsey, Quinton Dial, Mike Purcell, and Chris Jones. In no particular order, they have all seen playing time (some more than others) along the defensive line and have made their own individual impacts (some more than others) this past season.

Unfortunately, terrible tackling, improper scheme, inexperience, and lack of coaching has overshadowed the overall talent and production of this group. With the only true (speed) DE of this list being Blair, speed off the edge was truly lacking; however, this writer would love to see him get increased minutes as he learns and grows to be a true pro.

With the right defensive line rotation, scheme and proper coaching of this current 49ers’ roster (along with added pieces) can and will continue to get better, be competitive, and even see increased production sticking with the 3-4. The one piece missing from this defensive line to make this 3-4 even more effective and allow the linebackers to run downhill to fill gaps is a true and dominant 0 technique (nose tackle) to demand/occupy two blockers while clogging up the middle.

Ian Williams was that guy who provided a bright spot with potential and upside at the nose tackle position but was lost to injury, and due to the lack of production from that position, his loss truly hurt. While Dorsey flashed greatness with his ability to clog the middle and sniff out would-be running backs/plays, he’s not as young or explosive as he once was, so looking to add a talent like Dontari Poe, who’s amassed 157 total tackles, 13.0 sacks, and 12 passes defended within his five-year NFL career, (as a free agent) in the offseason or a guy like Solomon Thomas out of Stanford (via the draft/, who’s being compared to former 49er/All-Pro defensive linemen Justin Smith. When you get compared to a Justin Smith or mentioned in the same breath or conversation, being a potential addition could be huge for this 49ers team, to say the least.

These two additions would truly maximize this 3-4 defense. Adding an immovable force in the middle at nose tackle would allow the current linebackers, which will drastically change under this new regime no doubt (Ahmad Brooks, Aaron Lynch, Eli Harold, Tank Carradine, Navorro Bowman, Ray-Ray Armstrong, and possibly Melvin Ingram in free agency), to fill gaps, run downhill, and put the much needed QB pressure necessary from the front seven to help hurry, apply pressure, sack, and torment the quarterback. That alone will make it easier to make plays for the young but talented secondary, which was recently discussed on Niners Live and just scratching the surface.

4/3 breakdown at a glance:

Contrary to popular belief, while the 3-4 has been the 49ers’ base defense, a switch to the 4-3 isn’t as farfetched as it may appear with the talent on this current roster. It would take time, coaching, and adjustments but it’s possible. The first adjustments would be sliding Buckner and Armstead inside to defensive tackles and rotating with Dial, and Dorsey if kept. However, expect this position to be addressed in the draft/free agency/depth/impact player starting, etc. There’s strong sentiment for Purcell who seemed overmatched most of the season. He won’t return, but we will see.

The height, quickness, and arm length of both Buckner, Armstead, and Dial would help the 49ers inside against offensive guards getting off blocks and keeping their distance. Blair could also be an option at one defensive end along with moving Harold down to the front line to play defensive end with his hand in the ground coming off the edge, something he did quite frequently in college at Virginia where he amassed 17.5 sacks and 36.5 tackles for losses during his three-year career.

The linebacking core would consist of Bowman or Armstrong (Foster in the draft perhaps) at middle linebacker, via Niners Live where we recently discussed Foster being the heir apparent to Bowman; Brooks, who’s days with the 49ers may have come to an end; and Aaron Lynch, who’s been a disappointment/underachiever over the past year and a half, aren’t reliable options who can be called upon this day and age.

However, one could look to soon-to-be free agent Melvin Ingram who has 24.5 career sacks in his five-year career, which would be a viable option to play outside linebacker and apply the “heat on QBs” for this lackluster 49ers’ defense.

As aforementioned, with the right coaching and scheme, a 4-3 could work and based on fundamental thinking, the 49ers could and would benefit from the switch and even running a combination of both à la “hybrid.”

What’s the key? Maximizing the talent on the internal roster. In addition, from the 4-3 with the right personnel at the line of scrimmage/point of attack, the team wouldn’t have to rely on blitzing to get pressure as in the past. Last, but not least, the 4-3 is a one-gap defense that provides more control of the line of scrimmage with four down lineman versus that of a two gap defense like the 3-4 that requires three down lineman and less control of the line of scrimmage. Coaching and scheme could compensate for the lack of players having 4-3 experience.

Can I leave you with this? 

Both the 3-4 and 4-3 would be effective, moving forward. If the 49ers could somehow run a mixture of the two and even check from one to the other with minimal substitutions between the untapped potential of the current roster, maximizing the talent on this roster, and the addition of fresh blood in the coaching staff and on the roster via the draft or free agency, this team could be very competitive sooner rather than later. Needless to say, regardless of which direction the 49ers choose to go in, looking forward to a bright future and good things from this team is an optimistic goal that most fans have. As always, keep your #eyeswideopen

Welcome to

All records, statistics, and accolades are courtesy of, Pro Football,, unless otherwise indicated. Author, Kevin Mitchell new Staff Writer at Niners Live. Co-Author, Editor Niners Live.