White was selected in the first round of the Major League phase by the Pirates, who in turn traded him to the Mariners for cash considerations. The 25-year-old right-hander was 5-6 with a 4.40 ERA at Double-A Mississippi this past season.
With their 40-man roster full, the Braves didn't have the ability to select a player in this year's Rule 5 Draft.
White, who was selected by the Braves in the eighth round of the 2003 First-Year Player Draft, opened some eyes when he posted a 3.38 ERA in the eight innings he completed during Spring Training in 2006. But he was never viewed by the Atlanta organization as a legitimate Major League prospect.
The Mariners must keep White on their 25-man roster for this entire season. If they don't, they'll need to offer him back to the Braves at a cost of $25,000.
Mark Bowman is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.