Parsons averaged 7.2 points and 2.6 rebounds in three seasons with the Grizzlies. He has averaged 12.8 points and 4.5 rebounds in 435 career games with the Grizzlies, Houston Rockets and Dallas Mavericks.
Atlanta acquired Hill in a draft-night deal with the New Orleans Pelicans last month. The 28-year-old forward averaged 4.3 points and three rebounds in 44 games (15 starts) last season. Hill will make $12.8 million next season.
Plumlee averaged 4.4 points and 2.2 rebounds in 18 games for the Hawks last year. He is owed $12.5 million next season.
Hill has career averages of 5.9 points and 3.3 rebounds. Plumlee has averaged 4.9 points and 4.5 rebounds since debuting in 2012.
Both will be free agents after the 2019-20 season.