49ers bye-week grades: defense

While the offensive continues to try and figure what it's good at, the 49ers' defense continued to play well despite missing a number of key players. We took a look at each position and offered grades for their play through the season's first seven games.

Before we take a look at grades, here’s where the 49ers defense is statistically while players enjoy their bye week:

Total Defense (NFL ranks)

Scoring: 23.6 (20th)
Yards per game: 206 (2nd)
Yards per play: 5.2 (9th)
3rd-down conversion rate: 47.44% (29th)
Opponents Red Zone TD rate: 68.42% (29th)

Run Defense

Rush play rate: 36.67% (4th)
Yards per rush: 4.0 (12th)
Rushing yards per game: 84.9 (5th)

Pass Defense

Pass play rate: 63.33% (29th)
Completion rate: 58.70% (3rd)
Yards per pass: 6.3 (6th)
Pass yards per game: 221.1 (10th)
Sack rate: 4.63% (21st)
INT rate: 2.83% (11th)

A few notes: take away the 21 points allowed the Eagles in Week 4 that didn’t come from Chip Kelly’s offense, and the 49ers have allowed 20.6 points per game, which would rank in the top 10 of the league.

Otherwise, San Francisco’s patchwork defense is still ranked second in the NFL in yardage, despite allowing a season-high 419 in last week’s drubbing in Denver.

The biggest areas for improvement? Third-down and red-zone scoring. The 49ers are still near the bottom of the league in both categories. The leading culprit: the pass rush. It has gotten better as the season has gone on - thanks largely to Aaron Lynch’s insertion to the lineup in passing situations with the improvement of Dan Skuta and Ahmad Brooks. It will be aided significantly by the eventual return of top pass rusher Aldon Smith.

To the grades, calculated on an (*unscientific*) 100-point scale:

Defensive line: 91

Reasoning: The sack and tackle stats might not show it, but the team’s defensive line play has been outstanding in the first seven games. The production of Justin Smith, Ian Williams and Ray McDonald has helped mask the loss of NaVorro Bowman defending the run by allowing Michael Wilhoite to avoid blocks from offensive lineman.

The 49ers have the league’s fifth-ranked rushing defense and allowed more than 100-yards total in just three games this season (Cowboys, Chiefs and Broncos). Smith is healthy and playing at his highest level since 2012, before he sustained his torn triceps injury. Williams is having a standout season after undergoing four surgeries to repair his broken ankle suffered early in 2013.

They could afford to get to the quarterback more frequently, the return of Aldon Smith should help get Justin Smith in more one-on-one situations on passing plays.

Linebackers: 84

Reasoning: Patrick Willis continues to play at an All-Pro level amid the makeshift group. Wilhoite is continuing to get better in just about every phase. But the reason why this grade isn’t higher is largely due to the team’s outside linebackers that have struggled to pressure the quarterback.

Lynch and Dan Skuta have had good seasons, but Brooks and Corey Lemonier have been disappointments, bringing the grade down. Lemonier, who came into the season with high expectations, was surpassed by Lynch in Week 4 after registering just one quarterback pressure and hit in 70 pass rushing attempts, according to Pro Football Focus.

Brooks, a two-time second-team All-Pro, leads the defense with five penalties. His play has improved lately, and the addition of Smith will help him stay fresh while coordinator Vic Fangio will continue to keep in the rotation. Lynch is the 49ers’ best third pass-rushing option in years.

Cornerbacks: 86

Reasoning: Look at where the 49ers started the season with this group. They lost both their starters from the last three seasons in Carlos Rogers and Tarell Brown, inserted a player that missed his third season with an ACL tear, lost their No. 1 corner that made his first-ever Week 1 start, and played a rookie at nickel, arguably the toughest position to learn to defense.

The result? The league’s 10th-rated pass defense without having the luxury of good pass rush. The safety play has a lot to do with that, but Perrish Cox and Chris Culliver held their own without Tramaine Brock since Week 1 - before Brock came back and struggled against the Broncos. Cox has been one of the league’s best corners throughout the first seven games, making three interceptions and allowing 53.4 passer rating in coverage. Rookie Dontae Johnson has shown promise in his limited time on the field while Chris Cook is fitting well into his reserve role. And rookie Jimmie Ward was improving by the week before his quad injury kept him out of last week's loss.

Considering the volume question marks coming into the season, San Francisco’s corners have been a pleasant surprise. But as their weaknesses are dissected more and more by opponents on film, fighting off regression will be the mandate in the remaining nine games.

Safeties: 93

Reasoning: The defense’s best group through the first seven weeks. Antoine Bethea has been the right addition to replace the hard-hitting, and flag-collecting, Donte Whitner. Eric Reid is continuing to play beyond his years and is becoming an extension of Willis in the back of the secondary.

Prior to Sunday night’s shellacking, the 49ers allowed just 10 of 44 completions on attempts longer than 20-yards down field, which is a credit to the discipline and execution of Reid and Bethea. Neither had a good game in Denver, which dropped their grade a few points. But with the pass rush expected to improve, along with the eventual return of Bowman in the pipeline, the safeties should continue to play well as the season goes on.

*Statistics from Pro Football Focus were used in this report*


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