Sportsmen – and I suppose sportswomen as well – are often given nicknames by their team mates. For instance, Andrew Flintoff became “Freddy” because of the similarity of his surname to “Flintstone”. The most unimaginative of these is simply to add ‘-y’ at the end of the name, as in Jimmy Greaves becoming “Greavesy’ (“Saint and Greavesy”, “Saint” being Ian St. John, were a double act of TV football pundits).
It’s interesting, therefore, that when you get a footballer whose name actually ends in ‘-y’ (and is pronounced /-i/), the nickname involves removing that syllable. Rooney becomes “Roo”.