Out of bounds play

in a recent game,( I was not officiating) A1 took the ball out after made basket by B. B is pressuring full court. A1 cannot find anyone open so A2 steps out of bounds down the end line and A1 passes to him who then inbounds to A3. Legal?? I know it is legal to pass to another player out of bounds in this situation, but does the player without the ball need to be out of bounds prior to the ball becoming live?