Not much to go on here with a picture of just a few leaves. Appears to be a fungus of sorts. The most common maple problem seen at this time of year is tar spot. Doesn't appear to be your issue but can't be sure with so little to go on. http://msue.anr.msu.edu/news/why_do_my_maple_leaves_have_spots    Fungal problems at this time of year generally are not treated as it would have no effect. Fungicides no not cure. They can stop progression of the fungus but they do not cure. A positive ID would be required if treating anyway, and the only way to achieve the positive ID would be through lab testing. A Certified Arborist, one who specializes in everything woody, would do that for you and make recommendations. You can find one or more Certified Arborists in your zip code at www.treesaregood.com   Arborist evaluations are not expensive and can give you the piece of mind of knowing exactly what the problem is. While there, he/she would evaluate everything else in your landscape as well.

Or you could send a sample to Diagnostic Services for a small fee, for which you would get a positive ID along with recommendations. http://www.pestid.msu.edu/ 

Or you could focus on keeping the tree healthy with appropriate watering and fertilizing in spring. This approach would make your tree less likely to be attacked going forward. Trees often work through fungal problems on their own, particularly if kept healthy otherwise.  Whether you gain the positive ID or not, a good practice would be to rake up and discard the fallen leaves from the tree.  This so a possible overwintering fungus in the leaves does not reinfect the tree next season.  
 
Good luck!