Yes, Sirius was most likely far too rebellious to participate in team sports - in any way. He probably spent most of the game making snide remarks, catcalling, and possibly killing time by playing nasty pranks while everyone else was occupied.
Speaking of fanfic ideas, I'm presently trying to capture the details of a very strange dream from last night. I think it was something like a crossover betwixt The Matrix, The X-Files, and wouldn't have had the vaguest connection to Harry Potter save that it starred Sirius, Remus, and, for some strange reason, Peter Pettigrew. There wasn't even any animosity directed towards him, he was just ... there.
Anyway, it was interesting. Full of amusingly surreal Funhouse antics like blood dripping down the walls and mental headgames.