SANTA CLARA, Calif. -- The dramatic roller-coaster ride that has been the high-stakes contract negotiations between the San Francisco 49ers and wide receiver Brandon Aiyuk ended where it all began when this started more than six months ago -- with the Niners and Aiyuk sticking together for the long haul.

Aiyuk and the Niners on Thursday agreed to terms on a four-year, $120 million contract extension that will keep him in San Francisco through the 2028 season, sources told ESPN's Adam Schefter.

It's the same deal that has been on the table from the 49ers since Aug. 12, league sources told Schefter.

The extension includes $76 million guaranteed, with $47 million to be paid to Aiyuk before April 1, 2025, a source told ESPN's Jeremy Fowler.

Aiyuk joins Miami Dolphins star Tyreek Hill as the fifth-highest-paid receivers in the NFL with an average annual value of $30 million per season.

The deal comes on the heels of perhaps the most contentious move yet in these negotiations as the Niners publicly declared Aiyuk healthy on Wednesday with coach Kyle Shanahan and general manager John Lynch saying they expected him to participate in practice.

Aiyuk did not practice Wednesday or Thursday, opening himself up to the possibility of team discipline. Thursday's agreement, however, ensures Aiyuk can spend the next 10 days preparing for the Sept. 9 opener against the New York Jets.

For nearly two years before the extension was finished, the Niners maintained they always intended to re-sign Aiyuk. There was plenty of doubt about that outcome in recent weeks after the wideout requested a trade just before the start of training camp on July 23.

Not long after, the Niners -- for the first time -- seemed serious about trading Aiyuk.

With strong interest from the Pittsburgh Steelers, Cleveland Browns and New England Patriots, the 49ers and Aiyuk evaluated their options. To make a deal work, a team was going to have to satisfy both the Niners as well Aiyuk's demands for a lucrative contract extension.

While each of those teams was seemingly able to check one of those boxes, neither could do both, which helped the Niners and Aiyuk return to the negotiating table to work out their differences.

The result was a long-awaited deal that ensures the Niners' top wideout isn't going anywhere as San Francisco pursues the franchise's sixth Lombardi Trophy that has narrowly evaded it in four of the past five seasons.

Now the Niners not only have their best receiver for another run at the Super Bowl, but they can keep him with quarterback Brock Purdy as part of the team's primary offensive foundation for the next five years.

In 2023, Aiyuk had a breakout season, leading the Niners in receiving yards (1,342) while finishing ninth in the NFL in receiving yards per game (83.9), second in yards per reception (17.9) and first in yards per target (12.9) on his way to a second-team All-Pro nod. His return also means the Niners could have the same starting 11 on offense from last year, with Aiyuk able to team with fellow wideouts Deebo Samuel and Jauan Jennings, while rookies Ricky Pearsall and Jacob Cowing develop.