Sean White, a 1999 Mercer Island High graduate, made his debut with the Seattle Mariners Wednesday at Safeco Field against the Oakland Athletics. White pitched three and a third innings giving up one earned run on two hits and a walk, while striking out one in the team’s first loss of the season 9-0. White was traded to the Mariners in December as a Rule 5 Draft pick out of the Atlanta Braves organization, and attended spring training with the Mariners to compete for a pitching job.