With six different NFL clubs now eager to sign Jarryd Hayne I thought it would be interesting to put this latest code conversion in a historical and global context. Using this list of players who have played more than one code of football I generated this graph. The size of the nodes reflects the number of links too and from each code (these are known as edges in graph theory). The more red the colour of the node the more closely it is linked to AFL alone. Interestingly, Rugby Union and AFL have exactly the same number of edges. However, the AFL is the only code with edges linking to every other node which places it squarely at the centre of the international football universe. That is, more players have come to the AFL from other codes, or left the AFL for other codes than any other code.
One other feature of the graph is interesting to note, the two most interlinked codes are rugby union and league. As importantly, the exchange is fairly symmetrical. There is just a slightly stronger flow from union to league than from league to union. Compare this to the plight of gaelic football which is a serious net contributor to every code except the gridirons without getting much back at all!