The Japanese international has agreed terms with the Old Trafford outfit and is now awaiting a work permit and a medical before completing his €14.8 million (£12m) move.
The signing of the Borussia Dortmund midfielder is set to arouse interest from the Far East, raising commercial revenue for the Premier League runners-up, but Arnold insists that the potential revenue was not a contributing factor in the deal.
"We don't sign players to sell shirts," Arnold told reporters. "We are reliant on 25 players and they are all massive stars.
Arnold claims that the worldwide following the club have acquired is not down to one specific player, adding that the club have a squad full of superstars.
"We have 25 George Clooneys,” he added. “When you look at the success we've seen in that part of the world, it isn't down to any one player or person."