If you want to incorporate the logo, your best bet may be to use a photo file from a website and a program like stitchboard
I've seen some very successful blankets with American pro-football and college logos made that way. I don't think you're going to find written directions, however. Stitchboard will create a chart but it'll be workable.
You could also consider making the blanket in the colors of the team or with border stripes in the team colors. What about sewing a small patch of the team logo onto a corner?
Maybe you can answer a question for me? I've always wondered what the "united" in Leeds United or Manchester United means.