The Detroit Lions’ numbers are somewhat difficult to kern automatically because these are slanted. When you place them as vector paths, you have to visually kern since auto-align functions in graphics programs (like Adobe Illustrator) only detect the rectangular boundaries of an object instead of the boundaries of its actual shape.
So instead of eye-balling what looks right, an artist would have to construct the digital asset of a jersey like they would on a production floor for an actual on-field jersey or a replica consumer jersey. That is to digitally put out a guide or measurement and move the numbers closer together until the guides touch the second number.
This tact can also be taken for the Lions’ slanted numbers. But when building a font and using software to determine the spacing between numbers, it will give inconsistent results.
Therefore, in order to overcome the slant or skew of the numbers and then allow the font software to automatically generate kerning pairs, it’s helpful to un-skew, then kern, then re-skew the glyphs.
The fonts created for this typeface included the back, front, and TV numbers (each with slightly different kerning and proportions depending on various factors) and the letters typeface. They are or were in use on fanatics.com (backup link) to display preview images of custom products, generate custom products at production facilities, and outside of fanatics.com used to typeset name and number products with matching typefaces in use.
The Fonts generated for the Detroit Lions were a few of 330+ font files created for all NFL teams and jerseys for the 2020 season.