According to Shams Charania of The Athletic and Stadium, Richardson was fined $25,000 because he threw his shoe into the AmericanAirlines Arena crowd.
Ohm Youngmisuk of ESPN.com described the proceedings, noting Richardson thought official Kevin Scott should have called a foul on the Lakers when he drove to the basket in the fourth quarter. The contact from the drive knocked his shoe loose, which he showed Scott.
Richardson then threw his shoe against the scorer's table later in the quarter after he was whistled for a foul and eventually tossed it into the stands, drawing an ejection.
"I wasn't really thinking about much," he said, per Youngmisuk. "I was thinking about how frustrated I was. And going forward I can't let that happen."
Tim Reynolds of the Associated Press noted Richardson talked about the incident with the NBA office and understood he was going to be punished.
He was playing well prior to the incident and finished with 17 points and six rebounds on 7-of-11 shooting. However, he and his Heat teammates ultimately couldn't match LeBron James, who poured in 51 points in a head-turning performance in one of his old stomping grounds.
Richardson was likely frustrated with another loss for the Heat, who are 6-10 on the season and on the outside of the early playoff picture in the Eastern Conference.