Tenn. R. Evid. 606
Advisory Commission Comments.
While there is no Tennessee precedent, jurors could and did testify at early common law. This proposed rule would prevent a juror from switching from jury box to witness stand during the course of a trial.
After verdict, part (b) would come into play. A juror may testify or submit an affidavit in connection with a motion for new trial, but only in the limited circumstances of:
(1) "Extraneous prejudicial information" finding its way into the jury room,
(2) Improper outside pressure on a juror, or
(3) A quotient or gambling verdict.
This rule is the same as that adopted in State v. Blackwell, 664 S.W.2d 686 (Tenn. 1984).