Saleh, the linebackers coach for the Jacksonville Jaguars since 2014, was reportedly set to join the Los Angeles Chargers in the same role. Former Jaguars head coach Gus Bradley, who the 49ers tried to lure as their own defensive coordinator, joined the Chargers instead, and planned on taking Saleh with him.
Saleh was among two candidates interviewed last Friday for the vacant position on head coach Kyle Shanahan's staff. The other was Atlanta Falcons defensive passing game coordinator Jerome Henderson, who worked on the same staff with Shanahan in 2016.
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Saleh, 38, will be NFL's third-youngest defensive coordinator and the 49ers' first rookie defensive coordinator since Greg Manusky was hired in 2007.
Saleh's NFL coaching career kicked off in 2005 as an intern working with the Houston Texans defense. In 2006, he was hired as a defensive quality control coach for the Texans and then promoted to assistant linebackers coach in 2009. In 2011, Saleh joined the Seattle Seahawks as their defensive quality control coach, where he remained for three seasons. He was part of their 2013 championship season when they defeated the Denver Broncos in Super Bowl XLVIII.
The 49ers will reportedly return to a 4-3 defense, the same system that Gus Bradley runs and a system that Saleh has worked within since 2011. The move could be a big change for the 49ers' top draft picks over the past two years. Defensive lineman Arik Armstead and DeForest Buckner were brought in to fit the team's 3-4 scheme and work with edge defending linebackers on the outside. The transition might mean a shift in responsibility for one of those players. Of course, it is entirely possible that free agency or the draft addresses one or more of the needs necessary to properly shift to the 4-3.
Saleh worked with Gus Bradley's defense with the Seattle Seahawks and then went with him to Jacksonville when Bradley became the head coach. Saleh's experience with that system influenced Shanahan's decision to bring him aboard. Shanahan called Seattle's defense very sound, disciplined, and tough to go up against. That is what the 49ers want to create under Shanahan.
"They make you work all the way down the field," Shanahan said. "When someone makes you work all the way down the field, no matter how talented they are, you have to be on as an offense to score points because you can get to the red zone, you can get yards, but in order to get touchdowns, you have to execute. And it's a defense that makes you execute."
"Robert Saleh is as smart as anyone I've been around," Shanahan added. "He studies everything. He knows a lot of different systems but he knows the true Seattle/Atlanta/Jacksonville system inside and out as much as anybody I've been with."
In 2016, Jim O'Neil served as the defensive coordinator for the 49ers within Chip Kelly's staff. Under his helm, the 49ers defense ranked last in the league. The unit had given up an average of 31.0 points per game (32nd), 424.9 yards per game (32nd), and a league-high 176.3 rushing yards (32nd). No team in 49ers franchise history has given up more rushing yards than the 2016 squad.
