The Miami Heat are matching the four-year, $50 million offer sheet to restricted free-agent guard Tyler Johnson, thwarting the Brooklyn Nets’ bid to acquire him, league sources told The Vertical.

The Heat’s decision to retain Johnson was the second blow to the Nets on Sunday, a decision made within hours after the Portland Trail Blazers matched the Nets’ $75 million offer sheet on restricted free-agent guard Allen Crabbe.

Johnson’s contract included $18 million-plus and $19 million-plus “poison pill” provisions in years three and four of the deal. They were designed to severely puncture the Heat’s salary cap and dissuade president Pat Riley from retaining Johnson. Nevertheless, Miami was determined to hold on to a young guard that it had plucked out of the NBA Development League and continued to develop in the Heat system.

The Heat made orderly signings of Derrick Williams, Udonis Haslem and Wayne Ellington on Sunday, sequencing those contracts to facilitate the salary-cap machinations of a match on Johnson.

For Johnson, the contract represents one of the most rapid financial ascensions in recent league history: From an undrafted D-League guard in 2015, to participating in only 68 games over parts of the past two seasons, to a staggering market deal.

Johnson made $507,000 in his second NBA season for the Heat in 2015-16. He played 36 games – only starting five – but NBA executives and coaches who scouted him and studied him closely on tape in the D-League and NBA see the potential for a versatile and complete guard.

For the Nets, one possibility on the market could be a run at Oklahoma City Thunder restricted free-agent guard Dion Waiters, league sources said. The Nets have given some consideration to an offer, but will likely evaluate that in the next few days, league sources said.

Brooklyn is devoid of first-round picks in coming years, and new general manager Sean Marks has tried to be creative in bringing young talent into the organization.

Johnson was an undrafted free agent out of Fresno State in 2014. He missed nearly three months this season because of shoulder surgery but returned in the playoffs for Miami.

The Nets also signed unrestricted free-agent guard Jeremy Lin to a three-year, $36 million contract.