Aaron Lynch (59) is among the 49ers to get to Kansas City quarterback Alex Smith during a game in 2014. Paul Kitagaki Jr. The Bee
Aaron Lynch (59) is among the 49ers to get to Kansas City quarterback Alex Smith during a game in 2014. Paul Kitagaki Jr. The Bee

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San Francisco 49ers

49ers will head into 2018 looking for an ‘edge’ on defense

By Matt Barrows

mbarrows@sacbee.com

December 30, 2017 09:01 AM

SANTA CLARA

Walk-through practices are by definition low-key affairs. The 49ers’ Thursday-morning session, however, had an element of sizzle.

“Guys just yapping and talking and alerting each other to everything,” defensive coordinator Robert Saleh said.

To Saleh, it was the sound of cohesion. The chatter was the result of a defense that was besieged by injuries in the first half of the season but that finally has enjoyed a measure of continuity – and with it success – over the last month.

The team is allowing 3.78 yards per carry, which is more than a yard below last year’s average and one that ranks seventh in the NFL. No opposing rushing attack has had more than 100 yards against San Francisco since Nov. 12.

In that way, Saleh and his staff feel very good about their defensive middle going into next season.

The next step is sharpening the edges.

When it comes to the pass rush, the statistics aren’t nearly as promising. Only seven teams have fewer sacks than San Francisco heading into Sunday’s finale. The 49ers’ sack leader, Elvis Dumervil, has just 5 1/2. If that ends up being the team high, it would be the most paltry regular-season high since Fred Dean had 3 1/2 during a 1982 season that was reduced to nine games because of a players’ strike.

That lack of heat off the edge helps explain other dubious defensive stats:

▪ San Francisco ranks 29th in third-down defense, allowing a 43.7 conversion rate.

▪ Opposing quarterbacks have a 95.3 passer rating against the 49ers this season, eighth worst in the league.

▪ The 49ers have allowed the sixth most points in the NFL this season, 370, although that’s still 110 fewer than a year ago.

Saleh noted that it used to be that a defense could shore up its interior and not have to worry too much about much else. With offenses passing so much nowadays – and with defenses using their nickel defenses half the time – there is added importance on fixing the edges as well.

A stout defensive core, he said, will force third down.

“The edges, your (cornerbacks) and your edge rushers, are what get you off the field,” he said. “They’re the ones that get you off in two-minute (situations). They’re the ones that win in the red zone. And so in that regard it is a domino effect. We get to third down very, very easily. We’ve built leads here over the second half of the year. Now we need to as a defense, we need to learn how to close.”

The team is certain to make changes on the edge.

Four of the players who have played defensive end this season – Tank Carradine, Cassius Marsh, Aaron Lynch and Leger Douzable – will be free agents in March. Another, former first-round pick Arik Armstead, is entering the final year of his rookie contract. The team must decide whether to pick up the so-called fifth-year option on his deal, one that will lock him in through 2019 but which also would come with a significant bump in his 2019 salary.

The team’s defensive ends signed for next season include Dumervil, Solomon Thomas and Ronald Blair. Thomas, however, likely will be used as an inside rusher on passing downs, while Blair mostly has been a back-up at the “big end” position, which isn’t the primary pass rusher on the line.

Thomas and defensive tackle DeForest Buckner are tied for second place on the team in sacks. Each has three. They likely will be the primary interior pass rushers next season, Saleh said, and their sack numbers would benefit from a more formidable edge presence.

“I don’t want to take away from what they’ve been able to accomplish this year, but anytime you create those edges, that pocket gets very uncomfortable for a quarterback,” he said.

Matt Barrows: @mattbarrows, read more about the team at sacbee.com/sf49ers.