Depending on the deepness, which I am guessing looking at these that they aren't super deep, a good resurface where you start with a super low grit and do a 4 inch in diameter sanding circle (on the spinner) directly over the scratch and move outward in sanding radius diameter while moving up in grit would be best until the whole ball is resurfaced. Some people like using bevels and then sand, but that can leave flat spots and isn't suggested for anything in the track area, but still can be done well.
If you don't have a spinner, there are a couple products that are sprays that fill in the gap like super glue, but I still believe they need some form of sanding.
If the scratches are super deep, then you would need a drill and plug, which also requires sanding.