Could 49ers benefit as longtime rival Seahawks rebuild?

SANTA CLARA - The Seattle Seahawks’ sudden dismantling could be just what the 49ers need to snap a nine-game losing streak to their NFC West rival, dating back to the 2013 season’s NFC championship game.

An offseason exodus that started with widespread coaching-staff changes is being followed by the departures of Seattle’s star players who keyed a five-year playoff run and back-to-back Super Bowl appearances.

Shortly after Wednesday’s reports of cornerback Richard Sherman’s expected exit from the Seahawks, defensive end Michael Bennett got traded to the Philadelphia Eagles, ESPN reported. The future of other Seahawks mainstays and 49ers archenemies also are in doubt, such as safety Kam Chancellor and defensive end Cliff Avril, who sustained career-threatening neck injuries last season.

Remember what happened after the Seahawks swept the 49ers in 2014? Probably the NFL’s greatest turnover ever. Out went Jim Harbaugh and his top assistants, followed by a stunning wave of retirements (Justin Smith, Patrick Willis, Anthony Davis, Chris Borland) and free agency exits of Frank Gore, Michael Crabtree, Mike Iupati and more.

More Seahawks starters could be on their way out of town, too. Safety Earl Thomas might be traded, and, with no franchise tag in effect, free agency might lead to exits by tight end Jimmy Graham, wide receiver Paul Richardson and defensive lineman Sheldon Richardson.

The Seahawks went 9-7 last season and missed the playoffs for the first time since 2011. But they did sweep the 49ers again, toppling first-year coach Kyle Shanahan 12-9 in Week 2 and?24-13 in Week 12.

The Seahawks still have coach Pete Carroll and general manager John Schneider in place to turn out the lights (or install new bulbs, if you will). But Carroll’s staff has undergone sweeping changes and eight assistants were ousted, including at offensive coordinator (out: Darrell Bevell; in: Brian Schottenheimer), defensive coordinator (out: Kris Richard; in: Ken Norton Jr., after a one-week stint on the 49ers) and offensive line coach (out: Tom Cable; in: Mike Solari).

How will the Seahawks cope with such an overhaul? Well, the 2015 49ers set the bar low ?(5-11 under Jim Tomsula) before it went lower in 2016 (2-14 with coach Chip Kelly) and even lower with an 0-9 start under Shanahan last season.

But as the 49ers resurrected themselves with a 5-0 finish under quarterback Jimmy Garoppolo, the Seahawks lost three of their final four and set the stage for the shakeup we’re seeing now.

“They had a great finish to the season. He obviously added a spark to them, even in our game,” Carroll told reporters at last week’s scouting combine regarding the 49ers and Garoppolo. “It’s a great get for them. It’s going to be good for the division, for sure. It’s going to make it more challenging.”

Schneider, also speaking at the combine, said of Garoppolo: “He looked great. He looked phenomenal. I was kind of bummed out they got him.”

The Seahawks still have their own franchise quarterback, that being Russell Wilson, who’s been in the New York Yankees’ spring training camp.