Tree Frog

There are three treefrogs that have the light spot under the eye and may have this coloration: Cope's Gray Treefrog, Gray Treefrog (Hyla versicolor), and the Bird-voiced Treefrog (Hyla avivoca). I'm suggesting this as Cope's Gray Treefrog because of the location where you spotted this one. The Bird-voice Treefrog occurs in western TN and the Gray Treefrog is believed to occur only in extreme northeast TN (http://www.amphibiaweb.org/cgi/amphib_qu...).
The only way to differentiate between Cope's and the 'common' Gray Treefrog is by call or by DNA studies.
You can differentiate between the Bird-voiced and Gray treefrogs by the fact that the gray treefrogs have bright orange or yellow on the inner side of the back legs; the Bird-voiced Treefrog has pale yellow inner thighs.