CTMH has a
single football stamp.
They also have this "
Paper Pal Sports" set. (You can also get it with
matching thin cut dies.) I think it's meant to be used with this
base set like a paper doll, but if you're just looking for a jersey, just the clothes set might be right up your alley.
I am not a demonstrator, and the links go to the corporate page, not a demonstrator's. If you're interested in the stamps, but don't have a demo (and don't want to go through finding one), I can give you the contact info for mine.