If you are planning on brining your turkey today, read the label and proceed carefully. If you are cooking a commercially prepared bird, it almost certainly has already been brined, whether it is fresh or frozen. Most frozen birds have been injected with approximately a 15% solution containing salt. Fresh birds have also typically have been injected, but to a lower percentage.
If you have an injected bird and then you brine it, you will be serving a very salty bird. Instead of brining for flavor, simply break the membrane between the skin and breast, rub with oil and herbs of your choosing, and perhaps a little acid.
Feeling adventurous? Try lime, cracked pepper, and jalapeños. Mine will have a woven mat of bacon basting the breast as the crowning jewels!
Regardless of your approach, happiest of Thanksgiving wishes to you and your family.