Dominican baseball superstar Juan Soto has agreed to join the New York Mets on a record-breaking 15-year, US$765 million deal, multiple US media reports said on Sunday.

ESPN and Major League Baseball's official website both reported Soto's blockbuster move, which if confirmed would be the richest contract in the history of North American professional sport.

Soto had entered free agency after playing last season for the New York Yankees, who had hoped to re-sign the gifted 26-year-old outfielder.

The deal reported on Sunday eclipses the US$700 million, 10-year contract the Los Angeles Dodgers signed with Japanese star Shohei Ohtani last year.

ESPN reported that Soto's Mets contract could eventually be worth more than US$800 million if certain benchmarks were met.

The guessing game over Soto's likely next destination had dominated baseball's rumor mill since the Yankees were beaten 4-1 by the Dodgers in the World Series in October.

The Yankees had mounted a concerted effort to re-sign Soto, who blasted 41 home runs and amassed 166 hits for the Bronx Bombers last season.

However the Yankees were just one of several teams actively pursuing the explosive slugger, with the Mets and the Boston Red Sox amongst the teams who met with Soto's representatives to discuss a possible deal.

The Mets, however, won the race for Soto after a season in which they made a giant-killing playoff run to the National League Championship Series, where they eventually lost to the Dodgers.

The Mets will be the fourth team of Soto's relatively short career.

He exploded onto the Major League Baseball scene during his first full season in 2019, helping the Washington Nationals score an upset World Series victory over the Houston Astros.

He rejected a 15-year, US$440 million offer to stay with the Nationals in 2022, and was eventually traded to the San Diego Padres in August of that year.

But Soto failed to settle in San Diego and headed back to the east coast in December 2023 in a trade that took him to the Yankees. (AFP)