Richard Jefferson never played for the Celtics in his eight-team, 17-season NBA career, but he had a couple of memorable encounters playing against them.
He was a high-flying rookie on the New Jersey Nets teams that bounced the overachieving Paul Pierce/Antoine Walker Celtics from the 2001-02 Eastern Conference finals. (The Nets also eliminated the Celtics the following season.) In 2017, he was a nearly 37-year-old reserve on the Cleveland Cavaliers squad that bounced Isaiah Thomas and the Celtics from the postseason, again in the conference finals.
Jefferson has run into some interesting and successful Celtics incarnations over his career.