It would be futile to predict when, precisely, it will come. It is not possible, from the vantage point of now, of here, to identify a specific point, or an exact date, or even a broad time frame. All that can be said is that it will come, sooner or later. The days of heading in soccer are numbered.
The ball, after all, is rolling. England’s Football Association has received permission from the IFAB, the arcane and faintly mysterious body that defines the Laws of the Game — capital L, capital G, always — to run a trial in which players under the age of 12 will not be allowed to head the ball in training.