Shams Charania of The Vertical reported the news. Millsap was scheduled to make $21.4 million in the final year of his contract.
The four-time All-Star averaged 18.1 points, 7.7 rebounds and 3.7 assists per game in 2016-17. He will be the best free-agent power forward on the market and could land a contract worth upward of $30 million per season.
"I want to be here," Millsap told reporters after the Hawks' first-round playoff exit. "I think talks have been pretty good. ... It's something me, my agent and my family have got to sit down and talk about."
Hawks coach Mike Budenholzer has been a proponent of keeping the 32-year-old Millsap in Atlanta.
"The best for us is with Paul," Budenholzer said. "We're incredibly optimistic and incredibly committed to Paul."
While Budenholzer and Millsap seem to want this marriage to last, there is reason to believe it might not be so simple. Most teams won't want to hand a max-level contract to a player Millsap's age. He is a very good but non-foundational piece who likely won't translate to instant contention.
Budenholzer also lost some organizational power this offseason, ceding control of basketball operations. The Hawks are searching for a new general manager who may not want to hand Millsap something like $120-130 million over four years.