Tenn. Code Ann. § 12-3-507

Except as otherwise provided by law, a contract may be entered into by competitive negotiation when it is determined by the chief procurement officer that it is in the best interest of the state. Each use of competitive negotiation shall be subject to approval by the chief procurement officer and the comptroller of the treasury in accordance with rules, policies, and procedures of the procurement commission. Notice of such approved competitive negotiations shall be posted on the central procurement office's website.