San Francisco 49ers: 2018 Season preview, prediction and more

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SANTA CLARA, CA – DECEMBER 17: Defensive back K’Waun Williams #24 of the San Francisco 49ers celebrates after his team recovered a fumble against the Tennessee Titans during the second quarter at Levi’s Stadium on December 17, 2017 in Santa Clara, California. (Photo by Jason O. Watson/Getty Images) /

Defensive Preview

Pressure is the word that defines the 49ers defense in 2018. This is a unit that ranked 24th in the NFL in yards per game allowed and 26th in Football Outsiders DVOA, and it is their ability to capitalise on the pressure they generate that will be key in deciding whether Robert Saleh’s group is able to avoid again being a bottom-half defense.

The 49ers have the horses on the interior of the defensive line. DeForest Buckner is one of the NFL’s best pass-rushing defensive tackles but only had three sacks last season despite generating pressure almost at will. He is joined up by two fellow first-round defensive linemen in Solomon Thomas and Arik Armstead.

A third overall pick, Thomas needs to live up to that billing following a quiet rookie year, while Armstead will similarly be out to prove himself after what has so far been an injury interrupted career. He has little excuse not to perform following a switch to a big defensive end role much more suited to his skill set having been miscast as LEO last year.

Sheldon Day, Ronald Blair and Jullian Taylor are all versatile rotational pieces, the latter duo able play inside and out, but the significant amount of depth the Niners have up front will count for little if their edge players cannot clean up the pressures they produce.

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However, San Francisco’s edge talent is thin on the ground. Free-agent signing Jeremiah Attaochu did not make the final 53 and Pita Taumoepenu could only make the practice squad. That puts the emphasis firmly on Cassius Marsh and Dekoda Watson, who have 10 sacks combined for their career. Mark Nzeocha, the surprise starter at SAM linebacker, will also be expected to contribute pass rush when the 49ers are in their base defense.

The unheralded Nzeocha’s presence on the defense is indicative of the lack of depth at the linebacker. The cupboard will look particularly bare during the first two games when Reuben Foster is suspended, and rookie third-round pick Fred Warner will need to immediately impress to ensure Foster’s absence does not make too much of an impact.

Warner is part of the new breed of lighter linebackers whose main strength in coverage. With the passing game becoming ever more dominant, he will likely have a role even when Foster returns. Should Warner impress, he could leapfrog Malcolm Smith, a liability in coverage in his last season with the Oakland Raiders in 2016, on the depth chart and start alongside Foster, whose reputation as one of the best linebackers in the league will only grow if he performs as he did in 10 games in 2017.

Foster will be integral to the success of the defense, with perhaps only Richard Sherman more imporant. Sherman’s decision to sign for the Niners after being let go by the Seattle Seahawks was one of the biggest stories of free agency, yet it will have been for nought if he cannot stay on the field after returning from Achilles surgery.

However, if Sherman can stay healthy and be anything like the same player he was in Seattle, the 49ers will have a corner capable of locking down a side of the field whose experience will be invaluable in helping a young secondary to flourish.

Ahkello Witherspoon figures to the most direct beneficiary of Sherman’s wisdom, he is another candidate for a second-year breakout after improving markedly in coverage as a run defender in the second half of last season. Depth is a problem for the Niners, though, and San Francisco would be in trouble at boundary concern if either Sherman or Witherspoon went down, especially after versatile backup Jimmie Ward struggled substantially when deputising for Sherman in preseason.

Ward will, along with rookie D.J. Reed, serve as a backup at the nickel and free safety spots occupied by K’Waun Williams and Adrian Colbert, whose successful switch from cornerback to single-high free safety allowed the 49ers to fill a crucial role in Saleh’s Cover-3 scheme. Jaquiski Tartt will partner him at strong safety after a superb 2017 was brought to an early end by injury.

The arrow is pointing up for what has been a widely maligned secondary and the likes of Witherspoon, Colbert and Tartt should receive more recognition if they continue their upward momentum. Yet progress in the secondary and an improvement in the pass rush go hand in hand. For the back end of the defense to play at a playoff level, there has to be better production from the guys up front.