Along with Ball, the team inked centers Vernon Carey Jr. and Nick Richards, both second-round picks, on Monday. Charlotte also signed Grant Riller, a late second-round choice, and undrafted free agent Nate Darling to two-way contracts.
Ball, the No. 3 pick in this year's draft, played for the Illawara Hawks of Australia's National Basketball League, earning Rookie of the Year honors. He averaged 17 points, 7.5 rebounds and seven assists in 12 games and became the first player in the league since 2005 to record back-to-back triple-doubles.
Biyombo appeared in 53 games last season for the Hornets, making 29 starts. The 6-foot-9 center averaged a career-high 7.4 points, 5.8 rebounds and 0.9 blocked shots in 19.4 minutes per game.