[SwampeastMike]

A lasting, invisible repair of even a "clean" small tear in a high wear area can be impossible.

Shoe repair shops are a possibility.

If you want something inexpensive but quite visible, then sew it shut with a few, widely (say 1/4") spaced , staggered zig-zag stitches (think seam of a football) across the tear using a strong sinew, silk or polyester thread and a curved needle. Don't try to pull together--just hold in position--after applying cement (like Duco) to the edges of the tear itself. A less visible sewn repair is possible if you remove the cover and work from the back.