The Celtics are getting a veteran point guard who has spent 19 seasons in Memphis, Utah, and Minnesota, earning a reputation as one of the best teammates in the NBA. He is the Grizzlies’ all-time leader in points, assists, steals, 3-point field goals, and games played. Throughout those nearly two decades in the league, he has produced countless standout performances, including 27 30-point games, 108 10-assist games, and 94 double-doubles.