Butler announced his intentions in a Twitter post Monday, meaning the top two scorers from Baylor's 26-4 season are now exploring the draft.
The 6-foot-3 Butler led the Bears with 16 points a game, which was third in the Big 12 Conference. He was second in the league with 2.57 made 3-pointers per game.
Bears junior MaCio Teague, who was 10th in the Big 12 at 13.9 points a game, said last month that he was putting his name in the draft while keeping open the possibility of returning to Baylor. He was a second-team All-Big 12 pick.
Before the season was cut short because of the coronavirus pandemic, the Bears were the Big 12 runner-ups and spent five weeks as the nation's No. 1 team during a conference-record 23-game winning streak. They were No. 5 in the final AP Top 25 poll.
"To my teammates, this season was a special one, though it got cut short," Butler wrote in his tweet. "There is no other group of men I would've taken this journey with. We are brothers for life."