I got mine from Embroidery Library...

You could applique the letters of the team name on the shirt with the teams material
http://www.bunnycup.com had some letters that are about 3 1/2 inch tall when you put several together such as the Chicago Bears would be too wide but if you did say the large C and then in a smaller print center the words Chicago Bears in 1/2 inch letters would be good combination. Or you might get a football shape applique put on a shirt.

Marlem, you have been given two great answers here - let us know if you need more - *4U

Here are a bunch of football appliques; they are on sale today too.

There are free college sweatshirt type applique alphabet letters in Designs by Cuties, could use your material to make names, or names of teams with the letters? Good Luck, Marji