Since it'll be steamed, and not cooked with dry heat, you have less of a need for the brine. Also, the skin will be soft and not crispy.
But if you like the moist, flavorful meat that comes out of a clay roaster, you might do it that way, carve the bird up in the kitchen and serve the meat at the table, rather than the whole bird (a clay roasted bird does not make for that beautiful of a table presentation....).
I clay roast chickens sometimes, but generally like a browner, crispy bird. A turkey would not fit in my roaster, that's for sure.