On June 22, 2017, Butler was traded, along with the rights to Justin Patton (the 16th pick in the 2017 NBA draft), to the Minnesota Timberwolves in exchange for Zach LaVine, Kris Dunn and the rights to Lauri Markkanen (the seventh pick in the 2017 NBA draft). In his debut for the Timberwolves in their season opener on October 18, Butler scored 12 points in a 107–99 loss to the San Antonio Spurs. On December 3, he scored 20 of his 33 points in the fourth quarter of the Timberwolves' 112–106 win over Los Angeles Clippers. On December 12, he scored 38 points in a 118–112 overtime loss to the Philadelphia 76ers. On December 18, he had a 37-point effort in a 108–107 win over the Portland Trail Blazers. On December 27, Butler scored 12 of Minnesota's 14 points in overtime and finished with a season-high 39 to lift the Timberwolves to a 128–125 victory over the Denver Nuggets. On January 23, he was named a Western Conference All-Star reserve. On February 9, in his return to Chicago, Butler scored 38 points in a 114–113 loss to the Bulls. Butler chose to not play in the All-Star Game, prioritizing the stretch run of the season and thought the rest would benefit him. However, in the Timberwolves' first game after the All-Star break, on February 23 against the Houston Rockets, Butler left the game late in the third quarter with a right knee injury. Two days later, he underwent meniscus surgery and was ruled out indefinitely. Butler returned to action on April 6 to score 18 points in a 113–96 win over the Los Angeles Lakers. In Game 3 of the Timberwolves' first-round playoff series against the Rockets, Butler hit four 3-pointers among his 28 points in a 121–105 win. The Timberwolves went on to lose the series in five games.