I believe it can by using the chakra and taking from each a little chakra energy and along with Qigong or Chi you compress it into your hand. How do you do this? Well the reason why I mention Chi in this because there is this thing you do to gather Chi inbetween your hands by putting both your hands like a sphere on your heart but not touching your heart and breathing in and out until it expands unintentionally (without the person controlling the arms and hands basically expands by itself) This Chi sphere once big enough can be used as a frame or a airball or energy ball to be filled and once it is done you take one of the arms of the sphere and gather all the chakra in that arm with the other arm holding the Chi ball/sphere and with the empty arm with the chakra gathered there you slowly begin to fill the Chi ball until it is full. Once full you compress it. There you have a real life rasengan. If this theory does work then I doubt the “Rasengan” will have colour but it will be there.