Becoming Gramtically Correct 3 (Digital Rules Project)

More from Becoming Naomi León by Pam Muñoz Ryan . . .

” ‘Ms. Dominguez in case you don’t know, Blanca, is our principal.’ ”

It seems to me that “in case you didn’t know” is, in this case, a parenthetical phrase, and should therefore be set apart from the sentence by either parentheses or a comma–more likely a comma in this case because it seems a little more natural for dialogue and less stilted. Ryan used commas properly surrounding Blanca’s name but seems to have left out the very important parenthetical set that would make this sentence correct.

http://www.uhv.edu/ac/newsletters/writing/grammartip2006.08.29.htm