Tenn. Code Ann. § 25-3-109

It shall be a good defense to a motion against an officer residing in any county other than that from which an execution issued, for the officer to show by proof that in due time the process was placed in regular mail, at the courthouse of the county to which the execution was directed, with the proper return thereon, sealed up in the presence of the postmaster, directed to the clerk of the court from which the same issued.