One of the biggest issues was the trade of DeMar DeRozan to the San Antonio Spurs in the offseason.
"I felt betrayed because he felt betrayed, because that's my guy," Lowry said of the blockbuster deal, per ESPN. "That's my best friend."
Lowry and DeRozan spent six years together in Toronto, and they each earned four All-Star selections over that span. They combined to lead the Raptors to the most successful stretch in team history, including a franchise-record 59 wins last season.
Over the offseason, Ujiri sent DeRozan to the San Antonio Spurs in a deal for Kawhi Leonard, which Lowry clearly didn't appreciate. He described the late-night phone call during which he found out about the deal:
The 32-year-old continued to do his part of the pregame handshake even without DeRozan.
In 2017, Lowry signed a three-year, $90 million deal to remain in Toronto. The trade for Leonard has been working out, too, as the Raptors have a league-best 20-5 record.
If the Raptors come away with a championship this season, Lowry might change his attitude toward Ujiri.