Napier was a first-round selection after leading Connecticut to the 2014 NCAA title and played in 51 games for Miami, averaging 5.1 points and 2.5 assists. Dragic, the brother of Heat guard Goran Dragic, appeared in 16 games. Walker made 24 appearances for the Heat last season.
The moves cut about $4.1 million off next season's payroll, which also takes a sizable bit off Miami's projected tax bill for next season. Zoran Dragic earns $1.7 million this season, Napier will make about $1.3 million and Walker was due $1.1 million — $100,000 of which would have been guaranteed on Aug. 1.
Orlando sent a protected 2016 second-rounder to Miami for Napier. Boston sent a protected 2019 second-rounder for Zoran Dragic, while picking up a 2020 second-rounder and cash to cover his 2015-16 salary.
The Heat now have 14 contracts for next season, including three — Hassan Whiteside, Tyler Johnson and James Ennis — that are not fully guaranteed yet. That total of 14 doesn't include second-round draft pick Josh Richardson, who impressed Miami during summer league play in Orlando and Las Vegas earlier this month.
Miami can take up to 20 players to training camp, and is still expected to add shooting depth before finalizing the roster. Other trades to help create additional cap space and lessen tax ramifications would still seem possible, with Chris Andersen (due $5 million next season) and Mario Chalmers ($4.3 million) among the potential candidates if Miami goes that route.