Do pre constructed decks refresh standard rotation?
Theros (Theros, Born of the Gods, and Journey into Nyx) is the previous block; the current block is Khans of Tarkir block (Khans of Tarkir, Fate Reforged, and the as-yet-unreleased Dragons of Tarkir).  Both blocks are currently in Standard.  Under the current rules (which are changing next year), Standard always contains two blocks, and the older one leaves Standard when the next block is released.  Thus, unless they are reprinted in a newer expansion or Magic 2016, all Theros block cards will leave Standard when the next block starts in late September (or possible early October) of 2015.