He announced his decision in an open letter to fans published Friday in The Post-Standard of Syracuse. Reports that he would leave surfaced when the Orange were eliminated in the first round of the NCAA tournament.
"I have made the decision to embark on the next chapter of my life to pursue a professional basketball career," he wrote. "I am confident that I am ready because of you."
A year ago, Battle entered his name in the NBA draft but didn't hire an agent and ultimately decided to return for his junior year. He said then that he planned to re-enter the draft in 2019.
Battle is No. 70 on ESPN's rankings of the top 100 prospects.
His departure leaves a big void for the Orange. He has led Syracuse in scoring for the past two years and averaged 17.2 points per game this season. His 712 points in 2017-18 were the most for a sophomore in school history, and he led the nation in minutes played. His career total of 1,647 points is 16th on the school's scoring list.
The Associated Press contributed to this report.