One of the top freshmen during the 2013-14 season, Gordon was widely expected to leave after one season in Tucson.
Gordon was named the Pac-12 freshman of the year after averaging 12.4 points and 8 rebounds per game. He is a projected lottery pick, according to ESPN's Chad Ford, and is currently No. 6 on Ford's Big Board.
Johnson built up his draft stock with a superb junior season, earning numerous All-America honors and the Pac-12 player of year award.
Johnson led Arizona with 16.3 points per game last season while proving to be one of the nation's best perimeter defenders. He is a projected second-round pick, according to Ford.
Arizona (33-5) came within a point of reaching the Final Four, losing to Wisconsin in the Elite Eight.
Information from The Associated Press was used in this report.