On December 11, 2017, Ball signed with Prienai of the Lithuanian Basketball League (LKL) with his brother, LiAngelo.[50] Ball reportedly became the youngest American to ever sign a professional basketball contract.[51] The brothers' move to Lithuania was heavily reported by American sports media.[52][53] Prienai withdrew from the Baltic Basketball League upon their arrival and took part in various exhibition games sponsored by Big Baller Brand.[54] On January 13, 2018, Ball made his professional debut, going scoreless in five minutes against Lietkabelis.[55] On February 4, he scored a season-high 19 points, with four three-pointers and six assists, in a loss to Žalgiris.[56] In an exhibition game toward the end of the month, he suffered a leg injury that sidelined him for a month.[57][58] On April 25, Ball left Prienai with his family, with his father criticizing the team's head coach Virginijus Šeškus, in part because Ball did not receive enough playing time.[59][60] He finished the LKL season averaging 6.5 points and 2.4 assists, shooting 26.8 percent from the field, in 12.8 minutes per game.[61]