I have several balls w/ similar cracks around the finger and thumb holes. Have never had a problem w/ them getting too big or needing repair. My ball driller said if cracks are same basic shape as hole it is likely an "impact crack" from hitting pins, possibly even other balls on rack or stuck in pit, at exactly the correct angle. Drilling a hole changes the balls density, just enough, in the shape of the hole. A crack that goes in basically a straight line is a defect.