During the second half of Wednesday night's game against Spurs, the three-time All-Star was floored by a LaMarcus Aldridge screen as the Celtics trailed San Antonio. Walker became visibly upset that no foul was called, so he decided to vocalize his frustration to official Evan Scott. The 29-year-old athlete was subsequently hit with two technical fouls and ejected from the game.
Celtics head coach Brad Stevens also received a technical after shouting at the official.
According to the Boston Globe, this marked Walker's first ejection in his NBA career. He contributed 6 points, 4 assists, 3 rebounds, and 2 turnovers over 18 minutes playing time.
ESPN's Tim Bontemps and The Athletic's Jay King reported that the crowd was also outraged by the calls, with some spectators throwing objects toward the court.
The final score of the game was 129-114 with the Spurs winning.