Yes, I can verify It has been released as a Mass Market paperback. I have it in my collection and bought it the day it was released.
You may have to use eBay or Amazon Used Booksellers to get a copy at this point. Very few of those are in stock anywhere anymore, though I do see many of them on the actual shelves at B&N still.
Here is a recent article on the state of MMPs, which to me sounds like a death knell for the format. I have even noticed that almost all of the MMP sized books on the B&N shelves are being replaced with the clunky Trade sizes, so the article (sadly) seems to be true.
Is Mass Market Dying, Or Just Evolving—Again?