According to Jon Krawczynski of The Athletic, the warning signs began after the T-Wolves' first-round loss to the Houston Rockets. Rather than fly with the team back to Minnesota, he instead went to Los Angeles. He also refused to complete a medical exam that is usually part of exit interviews.
During the offseason, Butler reportedly "started conveying his concern for the franchise and casting doubts on his willingness to stay long term."
The 29-year-old can be a free agent after this season if he declines his $19.8 million player option.
Meanwhile, Butler reportedly clashed with his teammates, including Karl-Anthony Towns. In July, Joe Cowley of the Chicago Sun-Times reported the younger players' "nonchalant attitudes" rubbed Butler the wrong way.
Regardless of the reasoning, the guard is likely headed to another team before the start of the season.
According to ESPN's Adrian Wojnarowski, Minnesota owner Glen Taylor wants Butler gone within "the next several days."