A year -- and some roster tweaks -- have made all the difference for the 49ers' pass defense. 

San Francisco drafted Nick Bosa No. 2 overall this spring, traded for edge rusher Dee Ford and signed linebacker Kwon Alexander. With a much-improved front seven, the 49ers' standing pat in the secondary looks shrewd as the defense as a whole has coalesced into one of the NFL's best units. Their improvement defending opponents' passing attacks is especially stark, as Pro Football Focus' Jeff Deeney observed Tuesday morning. 

Last season, the 49ers defense ranked 31st, 10th, 13th and 32nd in those aforementioned categories. San Francisco is second, second, third and third, respectively, in them headed into Week 7 this season. 

The 49ers' road ahead will become more difficult down the stretch, however. Of the eight remaining opponents San Francisco has not yet played this season, six rank in the top 15 in passing yards per game. Those teams haven't necessarily faced a defensive front as formidable as the 49ers', though, and San Francisco's dominance against Jared Goff and the Rams' Sean McVay-coached offense bodes well for the rest of the 49ers' schedule. 

The improvement is not just owed to the 49ers' defensive line or the team's offseason additions, either. Their depth has played a big role, too. Jimmie Ward missed the 49ers' first three games with an injury, but he arguably has been the defense's most important player in the last two wins. Ahkello Witherspoon has not played since Week 3, but San Francisco hasn't missed a beat with Emmanuel Moseley starting in his absence. 

 

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The 49ers are clicking at every level of the defense, and it's possible they move up the NFL's statistical rankings in the next few weeks. They play lowly Washington in Week 7 and host Kyle Allen -- or Cam Newton -- and the Carolina Panthers in Week 8. Both teams' passing offenses rank in the bottom third of the league. 

In other words, the 49ers might just be getting started.