If soccer balls are the game piece, blue and red soccer balls would match the alliances nicely, but on the field they will have one brand. I don't think they will have a bunch of different brands on the field, but for practice I guess you could use any brand. The FTC hockey pucks last year I think were Franklin. So if we have soccer balls then I'm guessing they would want to use Franklin. Like these
http://www.toysrus.com/product/index...ductId=3540673
http://www.toysrus.com/product/index...ductId=3439879