49ers defense still hinges on Ahkello Witherspoon, K’Waun Williams

The San Francisco 49ers upgraded their pass rush during the offseason, but cornerback K’Waun Williams and Ahkello Witherspoon are still vital to the defense’s chances in 2019.

Every NFL team wants a good pass rush. And the San Francisco 49ers hope they’ll have one in 2019 after trading for edge rusher Dee Ford, then grabbing Ohio State’s Nick Bosa with the No. 2 overall pick in the 2019 NFL Draft.

But simply having a good pass rush doesn’t always equate to defensive success. Just ask the 2018 Kansas City Chiefs, who had a league-leading 52 sacks on the year but also surrendered the second most points in the league and had the ninth worst scoring defense.

Yes, a good pass rush erases a lot of things. Yet it doesn’t eliminate the need for quality cover players, especially cornerbacks.

The Niners secondary struggled in 2018, ranked by Pro Football Focus dead last once the season was done. A big reason why was cornerback Ahkello Witherspoon, who was PFF’s worst graded corner out of 112 qualifiers last season.

Quarterbacks targeting Witherspoon in coverage posted a combined passer rating of 98.0. And they targeted him a lot on the boundary — a team-high 68 times, which is an awfully high number when lined up to his opposite number, Richard Sherman, who was targeted only 40 times.

Witherspoon also surrendered a team-high five touchdowns on the season, too.

It’s possible opposing offenses look to target the 31-year-old Sherman a bit more in 2019. But his name alone could keep those quarterbacks from looking his direction. Especially with Witherspoon having to prove a lot after last year’s sub-par efforts. Why not look Witherspoon’s way, essentially?

Equally important, however, will be nickel cornerback K’Waun Williams‘ coverage assignments.

Williams was easily the second most-reliable corner on San Francisco’s roster behind Sherman. And while quarterbacks posted a 107.4 passer rating targeting Williams last year, he allowed a team-best-at-the-position 0.89 yards per snap. And his 66.7 overall grade on the year was second only to Sherman at the position, too.

Still, both Williams and Witherspoon expect to be the prime cover guys targeted this upcoming season.

Why? Because quarterbacks are focusing on quicker releases now than ever before. This 2018 article by The Ringer explains it:

"It is harder than ever for a team to stop the pass rush and harder than ever for the pass rush to work on a quarterback. A few years ago, coaches realized that shorter, quicker passes were more efficient than longer ones. For example, the number of yards Drew Brees has targeted on his passes has dropped each year for the last five, according to AirYards.com."

Quick, short passes have become a standard M.O. in the NFL, setting up deeper passes when the opportunity presents.

One of the effective means is to call for slants, especially on the inside where Williams will be defending. That’s why his performance in 2019 is important.

As far as Witherspoon, teams will again look to take advantage of what was a forgettable 2018 campaign. If those efforts repeat, the Niners may be forced to consider some other options. If they don’t, however, Witherspoon’s stock level should bounce back nicely.

Of course, all this is based on the given both Witherspoon and Williams secure starting roles for the 49ers this season. That’s yet to be determined. But given what happened last year for the two, San Francisco needs both to perform in a big way this season for it to be considered a success.

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