Maple trees are susceptible to pests and diseases and most have relatively thin bark that is quite easily damaged. A wound like the one pictured makes your tree vulnerable to diseases and insects.
Where the damaged area is less 25% of the trunk’s circumference, the wound should heal without permanent injury. Here’s a link that describes how to deal with the peeled bark here. It is important to cut back the wounded area to the point where bark is sound and firmly attached – this will enable to three to callous over properly.
Should you consider cutting back the wounded area, although the damage on your tree seems less than 25%, before starting, make sure your knife is clean. This can be achieved by dipping the blade in rubbing alcohol (70% isopropyl alcohol) or rinsing it with diluted household bleach (1 part bleak to 3 parts water). Dry the knife off well with a clean cloth or paper towel before using it.