The 6-foot-7 forward suffered a gruesome leg injury in his Celtics debut, and other injuries also sidelined him throughout the remainder of his tenure in Boston.
Despite the hardships, Hayward still looks back fondly on his three seasons in Beantown.
"There's no ill will on my end from anybody within the Boston organization, the players," Hayward told reporters Tuesday, according to ESPN's Nick Friedell. "I had an unbelievable time in Boston and I think that it's unfortunate what happened; I obviously had a freak injury right when I got there. And there's a lot of things that were kind of out of my control when I was in Boston.
"But I had a great time there and still have great relationships with the people there and some of the players there."
Hayward, who added that he also holds no "ill will" toward Boston, didn't live up to the four-year, $128-million contract he signed with the Celtics in 2017, though he showed signs of his previous All-Star form last season.
The Butler product averaged 17.5 points, a career-high 6.7 boards, and 4.1 assists across 52 appearances during the 2019-20 campaign.
Hayward inked a four-year, $120-million contract with the Charlotte Hornets after declining his $34.2-million player option with the Celtics for the upcoming season.