Many years ago, an herb lady told me that perennial herbs must have a winter dormancy (this doesn't include tender perennials). There's a slim chance there's some life in the roots but I wouldn't expect to see any signs of life until next spring.

If, as you describe, the soil had totally dried out for any extended period, the roots likely will not simply have gone dormant, but dried completely and therefore are beyond resuscitation.

You could try (though I would give this almost a zero chance of success) removing the plant from the ground, shaking off all soil, and soaking the root ball in a container of water for a few hours (I'd use a solution of Maxi-Crop, which helps with transplant shock, among other things), then repotting it into barely moist potting medium.

(Keep in mind that plants that go dormant in winter still have the benefit of moisture present in the ground over the winter. Your indoor plant was not "choosing" to go dormant! LOL)

My English/French/winter thyme plants (I have seen Thymus vulgaris sold under all of these names!) is quite happy outdoors year-round here in central OH, in open ground and also in a raised bed situation and remains green and harvestable throughout the winter. It has stiff, upright stems. Other T. vulgaris I have seen for sale has a more prostrate habit and softer, more tender stems and does not seem as hardy. My variegated thyme and lemon thyme also thrive through the winter outdoors - again whether in a raised bed or flat ground.

Be sure your soil in the garden drains well, though, if you want your herb(s) to do well. Also, once you get some re-established, be sure to harvest some in the summer to dry for winter so you have a good supply & do not have to brave the elements when you want to season your pot roast. :-)

Good luck!

Thank you!!