Legal Play or NOt

[mrerrl]

Team A has the ball 1st and 10 on their 40. They huddle up. After the white hat blows in the clock and ready for play, Team A subs in 1 player. As the player comes on the field 2 players leave the huddle for the sideline. Player A leaves the field and Player B stops outside the numbers. The team then breaks the huddle into an offensive formation and snaps the ball. They throw a deep pass to the player who did not leave the field. Is this legal. He meets all the necessary requirements of being inside the numbers before the snap and also never leaves the field of play. It is deception but the defense had the opportunity to see him leave the field and to cover him.