The Mariners announced the hiring Monday. Jewett has spent the last three seasons on the coaching staff of the Washington Nationals. He started as a major league coach for the Nationals, became their first base coach on July 1, 2011, and spent last season as their third base coach.
Prior to joining the Nationals organization, the 49-year-old Jewett spent his entire baseball career as a player and coach with the Pirates organization. He was the third base coach for the Pirates during the 2001 and 2002 seasons when McClendon was Pittsburgh's manager.