Onu, 23, is 6-foot-11 and played for seasons at NAIA school Shawnee State. He was named first-team All-American and Mid-South Conference Player of the Year.
Onu is a native of Cleveland and played high school basketball at Richmond Heights, Ohio.
Per Hill, the deal includes “Exhibit 10 language.” An Exhibit 10 contract is a one-year, minimum salary deal that does not include the possibility of bonuses.
Onu played for the Mavericks summer team in Las Vegas, though a knee injury forced him out of action in the final game.
Dallas now has 18 of a possible 20 players under contract for training camp.