Barnes had said for months he would likely make the move, hoping to get a long-term deal to return to Orlando. He made his intentions official Monday after the team's end-of-season meeting.
Barnes worked his way into the Magic's starting lineup this season, averaging 6.4 points per game in the playoffs. The defensive stopper's primary role was to guard opponents' best perimeter player.
The 30-year-old forward has played for seven teams in seven seasons in the NBA. He prefers to remain with the Magic.
Barnes hopes he impressed the Magic enough for them "to bring me back and give me something decent."