Shams Charania of The Athletic and Stadium first reported word of the deal.
The 23-year-old has one year remaining on his current contract before he's eligible to become a restricted free agent ahead of the 2021-22 NBA season.
Most expected the Heat to re-sign the 2020 All-Star, especially after his breakthrough this past year. He averaged 15.9 points, 10.2 rebounds and 1.3 blocks. The only real question was when Miami would formally table an offer.
ESPN's Brian Windhorst said Monday on Keyshawn, JWill & Zubin that the Heat had an incentive to wait on re-signing Adebayo since they'd potentially have the salary-cap space to pursue a star free agent next offseason.
Giannis Antetokounmpo is the obvious target for Miami and other championship contenders, but he's far from the only marquee name poised to hit the market. Making a big splash in free agency isn't impossible for the Heat but will become much harder with Adebayo's pay raise set to be locked in now.
Ira Winderman @IraHeatBeat
Adebayo's contract can be close to $200 million depending on super-max considerations. Heat would need to jump through a lot of hoops to also add max free agent next summer. But now have ample assets for sign-and-trade for one next summer, or a deal this season. https://t.co/qcLfXd2sDL
Keith Smith @KeithSmithNBA
Few things with Bam & MIA doing a contract extension now: -Takes away somewhere between $13-$18M of 2021 cap space -Heat can still get to max space, but it's definitely harder without moving some guys -Bam & Giannis share an agent, so there could be some early knowledge here
The Athletic's Eric Nehm noted Antetokounmpo and Adebayo share an agent, Alex Saratsis.
Perhaps the Heat's front office is getting the impression Giannis is leaning toward signing a supermax deal to remain with the Milwaukee Bucks. In that case, rewarding Adebayo for his breakout makes sense over preserving salary-cap space that can still be created again anyway—albeit with some more work required.
The 2017 first-round pick has watched some of his peers get paid handsomely. De'Aaron Fox was the first to get extended, pledging his future to the Sacramento Kings. Utah Jazz star Donovan Mitchell and Boston Celtics star Jayson Tatum were the next two to cash out.
Now, it's Adebayo's turn.