Go to this LINK
and see if any of the charts on this page are helpful. There are several with circles. One I noticed that seems to have close to the number you need is one in black, red and white with a big "F" on it. The inside of that circle is about what you need. If none of them work maybe they will help you figure out how to make a nice circle. A circle will always be kind of jagged looking but from a distance will look pretty good.
The link wouldn't take you right to the page, so you have to navigate a little. On the first page it brings up, look on the right for a link called "Knitting Patterns". When it brings up that page, look on the left for "Soccer Logos". When it brings that page up, when I clicked on any one of the logos it brought up charts for all of them. Lots of circles. Hopefully something will help.