This could be the American Legion Post 16 in Slatington basketball team. That is my guess since this postcard was in a lot with other Slatington photos. The American Legion was organized in Slatington in 1919.
My guess is that this is a Slatington team because it looks like the site of the old baseball field, the "S" on the uniforms, and the other photos in the group were all from Slatington.