Nose Tackle: Earl Mitchell
Left Defensive End: Arik Armstead
Right Defensive Tackle: DeForest Buckner
Right Defensive End (LEO): Aaron Lynch
A year removed from giving up more rushing yards than anyone else in the NFL (2,654), the 49ers defensive line should be slightly better aligning to a 4-3 base front.
This formation will emulate what the Seattle Seahawks have done — a 4-3 under with elements/personnel of a 3-4.
Recently signed defensive tackle Earl Mitchell will line up at the nose, replacing an aging and injury-concerning Glenn Dorsey in the middle of the line. Second-year pro DeForest Buckner should wind up in the right defensive tackle spot, while third-year pro Arik Armstead holds down the left defensive end position.
Armstead could lose out to backup defensive tackle Quinton Dial, especially in run formations, but one should suspect the Niners have more stock invested in Armstead’s development.
The key question is at the right defensive end, or LEO, position. This is reserved for the team’s best pass-rusher, but the 49ers got only 1.5 sacks out of linebacker Aaron Lynch in a shortened campaign a year ago.
So it wouldn’t be surprising to see the Niners add a more prolific pass-rusher via the NFL Draft this offseason. There should be a few available.