Kevin Durant shook the N.B.A. in the opening moments of free agency Sunday night, announcing his decision to leave the Golden State Warriors for the Nets on Instagram to the beat of a track from the Brooklyn rapper Notorious B.I.G.

For the Nets, who also struck a deal Sunday with Kyrie Irving, it was the splashiest combination of moves they could have made after spending years digging out from the depths of ill-advised personnel moves and searching for a slice of the spotlight in a city long dominated by the Knicks. For Durant, 30, it will be a fresh start with a new team — a budding relationship that will require patience from both sides.

Durant, a 10-time All-Star, will likely miss the 2019-2020 season after rupturing his Achilles’ tendon in the N.B.A. finals three weeks ago. Achilles’ injuries are often debilitating for elite athletes, and there is no guarantee that Durant will make a full recovery. But he is a unique talent — perhaps the most versatile scorer on the planet — and the Nets are betting big.