This is eye spot or Phyllosticta leaf spot, a common, but primarily cosmetic fungal disease that affects maples (in particular Amur, Japanese, red, silver and sugar maple). These spots have tan to brown centers and typically a purple, red, or brown margins. Tiny, black, pimple-like reproductive structures (called pycnidia) often form within the spots, and are used for diagnosis. As spots mature, the centers may fall out, leaving roughly circular holes.

This leaf spot is caused by the fungus Phyllosticta minima which overwinters in leaf litter. In the spring, rain and wind move spores of the fungus from the leaf litter to newly developing maple leaves, where infections occur. Spores produced on infected leaves can lead to additional infections within the tree canopy throughout the growing season.

Although leaf spot may look unsightly, the disease is usually only a cosmetic problem, rarely causing significant damage to mature and vigorously-growing trees. Occasionally, the disease may defoliate trees early in the growing season, but these trees are typically able to produce new leaves within a few weeks. Defoliated trees should be watered (about one inch of water per week), and properly fertilized (based on a soil nutrient test).

Compost, bury or burn leaf litter from infected trees in the fall, or in the spring before trees re-leaf. Newly planted maples, and established maples that have been severely affected by leaf spot for several years, may benefit from treatments with a fungicide containing chlorothalonil, copper, mancozeb, neem oil, sulfur or thiophanate-methyl. Three treatments may be needed for adequate control: one at bud break, one when leaves are half expanded, and one when leaves are fully expanded.

We would not recommend treatment unless you see this problem every year (in which case you should probably get a different tree). It's likely that you will rarely see it, and even then it will not affect the health of the tree. 

ECN