Leonard was introduced to a chorus of boos, and a relentless chant of "traitor" showered the All-Star forward while shooting free throws late in the second quarter.
The chants impacted Leonard for a moment as he stepped away from the free throw line to compose himself. He eventually shrugged off the chant and drained the first free throw before missing the second.
Spurs fans were yelling "traitor" at Kawhi 😮 pic.twitter.com/rGZqiONeUB— ESPN (@espn) January 4, 2019
The Spurs dominated for a majority of their 125-107 victory over the Raptors at the AT&T Center in the teams' first matchup since the offseason blockbuster trade.
Spurs guard DeMar DeRozan, who was part of the trade package that sent Leonard to the Raptors, posted his first career triple-double with 21 points, 14 rebounds and 11 assists.
Leonard dropped 21 points (8-of-13 shooting) and dished out five assists.
The 6-foot-7 Leonard, who guided the Spurs to an NBA championship in 2014, forced a trade to get out of San Antonio last year after a mysterious quad injury fractured his relationship with the organization and fan base.
The deal sent DeRozan and Jakob Poeltl to the Spurs, and moved Leonard and shooting guard Danny Green to the Raptors.
After the game, Popovich defended Leonard and his decision to demand a trade.
"I felt badly about it," Popovich said about Leonard being jeered by fans. "Kawhi's a high character guy. We all make decisions in our lives what we're gonna do with our futures, and he has the same right."
Leonard has led Toronto to a 28-12 record this season while averaging 27.3 points, 8.2 rebounds and 2.8 assists.