Fields, 28, joined Kansas City a year ago in the Mark Teahen trade. Hip surgery took up most of his Royals career, though he had 104 interesting pro plate appearances before being non-tendered this month. Beyond the hot corner, he's dabbled at first base and left field.
Fields was drafted 18th overall by the White Sox in 2004 and was once considered a top prospect. He crushed 23 home runs in 418 plate appearances with the Sox in '07, nine of which came in August of that year. Earlier this month the Pirates added another former top third base prospect in Andy Marte, cutting a third one loose in Andy LaRoche.