A Troubling Along the Border(1991)
(The second book in the Zarathandra series)
A novel by Donald Aamodt
"Sandy MacGregor doesn't want to be a hero. He has been unwillingly transported through time and space to the planet Zarathandra. He is being used for selfish purposes by a power hungry Goddess. He's stuck on the Rithian border where a rebellion brewing for centuries is about to explode in his face. And now, accompanied by an ancient desert scout and a bumbling sorcerer whose magic does more harm than good, he must journey to a dread region between the worlds to confront the evil usurper behind the realm-shattering revolt. Sandy would certainly prefer a destiny that was considerably less dangerous...but that's life."
Used availability for Donald Aamodt's A Troubling Along the Border
December 1991 : USA Paperback