A person with direct knowledge of the agreement confirmed the terms to The Associated Press on Friday night. The person spoke on condition of anonymity because Winslow isnt signing the contract until this weekend.
Winslow averaged 7.5 points and 5.3 rebounds on 41 percent shooting over his first three seasons, playing mostly as a reserve. He was the No. 10 pick in the 2015 draft out of Duke.
The contract means the Heat salary commitments for the 2019-20 season, when Winslows extension would begin, are about $135 million for 10 players.
ESPN first reported the agreement.
Winslows 2017-18 season got a boost when the Heat swung a February trade to bring back Dwyane Wade to Miami. Winslow was averaging 6.8 points before the trade; he averaged 9.8 points after Wade returned.
“Justise is ready to make another jump,” Wade said earlier this preseason. “I think with him, the big thing is health. When hes healthy, hes a big part of this.”
Winslow was held out of Miamis preseason finale against Atlanta on Friday night, with Heat coach Erik Spoelstra making the decision to give him rest. Miami opens the regular season at Orlando on Wednesday.