Nobody uses the brothers soccer field anymore, what if it was redone with a different named sport Unique to graal but basically soccer, just needs to be soccer like to fit the theme on graal, just use the leather ball skin or a skin like that, use the goal things to be scripted to record the points , and have the same ctf system of splitting into teams, and have a gimmick or something to make it a bit different to soccer.
Maybe like archery there could be a score board and prizes, I could do any gfx or designs for it, in fact if I got the go ahead I can suggest some graal related things that would make it unique from modern soccer. Maybe the soccer ball shop in it could just be a ball shop, to keep with the medieval theme.