This post is one of a series on ‘Germanisms in American English’ and should be read in conjunction with the introductory post here.
Apart from the obvious meaning of ‘someone who is keen on sports’, the above terms have an additional usage in American English (AmE) and German which I’ve never encountered in British English (BrE). The first time I heard sports fan used in this way was in the mid-1990s, by a colleague from Buffalo, New York, who explained that it was an informal term of address used by an older man to a boy – something like ‘my lad’ in British English. This explanation is similar to the following definition of sports fan in Urban Dictionary (a crowdsourced online dictionary of slang):
» A nickname used by working class old timers in and around the gulf coast united states. Typically used in greeting towards a younger person. […] Ironically it has absolutely nothing to do with sports or sportsmanship.
Hows it going ‘Sportsfan’? «
[Contributed by Jonathan L. on 30/04/2013; No.2-ranked definition as of 26/11/2016.]
The Duden dictionary also defines Sportsfreund as a male form of address:
» saloppe Anrede an eine männliche Person
nicht so schüchtern, Sportsfreund! «
Casual form of address to a male person
don’t be shy, sports fan!
But this is Duden’s second-listed definition of Sportsfreund; the primary definition refers us to the synonym Sportfreund (the same as Sportsfreund but without the linking ‘s’). Sportfreund has two meanings in Duden, the first of which is ‘Freund, Anhänger des Sports’ (fan of sports), and the second of which is ‘Sportkamerad’ (fellow sports player). It seems that Sportsfreund (with linking ‘s’) can have both of those meanings, too, but in addition it has its own unique usage as a casual form of address, which has become divorced from any real sporting context.
I speculate that this non-sporting use of Sportsfreund was what gave rise to the equivalent use of sports fan in AmE. If we imagine German immigrants* to the US encountering the term sports fan for the first time, it’s easy to understand how they might start using it not just to mean ‘someone who is keen on sports’, but also as a casual form of address – influenced by that use of the term Sportsfreund in German.
* Most German immigrants arrived in the late 19th–early 20th century, and the word Sport first appeared in the Duden German dictionary in 1887, which supports the hypothesis that Germans would already have known the term Sportsfreund when arriving in the US during the period in question.