Are the 49ers still using a nose tackle? Are the safeties truly interchangeable? Why the sudden interest in sub-6-foot cornerbacks like Jason Verrett?



The team’s defense seemed to undergo a sea change on the defensive side of the ball this offseason, leading to a broader question about the unit: Is this still the same defense Robert Saleh installed when he became coordinator in 2017?



It is, Saleh said in a recent sit-down interview with The Athletic. It’s just one that better reflects a league that in recent years has shifted heavily toward the passing game and three- and four-receiver formations.



Saleh spent nearly 45 minutes answering questions about scheme and personnel. Among the major themes to emerge:



• The 49ers have dedicated the offseason toward tweaking their base defense so that it better resembles the nickel alignments, which are used the majority of the time. A year ago, opponents tried to put the 49ers into their...