Athletes need short memories.

Four years ago, cornerback Richard Sherman made one of the Seahawks’ defining plays of the decade, tipping the ball to Malcolm Smith for a game-ending interception against San Francisco to send Seattle to Super Bowl XLVIII. Now, Sherman has reportedly agreed to sign with the 49ers for $39 million over three years, stunningly switching to the other side of one of the biggest rivalries in the NFL and further widening the gap between the rising 49ers and sinking Seahawks.

The agreement comes just one day after the Seahawks released Sherman in order to save $11 million in cap space. The three-time All-Pro ruptured his right Achilles against the Arizona Cardinals on Thursday Night Football in Week 10. He had surgery on that injury and also underwent a cleanup procedure on his left Achilles this offseason, but is expected to be ready for training camp.

Sherman, a Compton native, played college football in the Bay Area, at Stanford. As his free agency began, his “strong affinity for the West Coast” surfaced in reports about his potential landing spot. Par for the course for those moving near Silicon Valley, Sherman’s new job in San Francisco is giving him a raise, as he’ll earn roughly $2 million more this year than he would have in Seattle. That figure is even more impressive considering he’s been serving as his own agent for the last year.

After a half-decade of retaining the most dominant defensive core in football, Seattle is experiencing an identity crisis, and Sherman was cut during the Seahawks’ firesale facelift. For the 49ers, it’s a worthy gamble that the healing Sherman will be able to return to his previous level of play, this time for a team that had nearly $70 million of cap space remaining even after signing Jimmy Garoppolo to the highest annual salary in NFL history last month. Sherman said he wanted to go to a contender, and despite the Niners’ 6-10 mark last season, they enter 2018 as a stronger bet in the NFC West than Seattle after finishing 5-0 under Garoppolo and armed with enough cap space to control free agency.

Sherman was once San Francisco’s leading cause of football-related nightmares. This weekend, he’s the 49ers’ most welcome addition. Four years after tipping that ball to Smith, he may be the piece that tips the NFC West to the 49ers. Rivalries come and go, but business is always business.