May's addition was one of five moves in the Minor League player development staff announced by general manager Jack Zduriencik.
John Stearns, who had a 10-year career as a catcher with the Mets and has most recently been working as a Major League scout with the Mariners, will now take over as the Minor League catching coordinator. He replaces Roger Hansen, who was recently promoted to a special assistant to the general manager position.
Longtime Mariners coach Gary Wheelock, who was the pitching coach with the Rookie League Peoria squad the past eight years, will become Minor League rehab pitching coordinator.
Jesus Azuaje, who spent the past two seasons as manager of the Mariners rookie-level Arizona Summer League squad, takes over as Latin America field coordinator.
Jimmy Southard, a former trainer and assistant medical coordinator with the Rays and D-backs, has been hired as the Mariners Minor League training coordinator.
May Jr., the son of three-time All-Star first baseman Lee May, replaces Rick Down as the primary Minor League hitting coordinator. May Jr. was a first-round Draft pick of the Mets in 1986 and played eight seasons of Minor League ball with the Mets and Royals before getting into coaching.
He most recently was hitting instructor for the Columbus Clippers in the Indians organization in 2010-11. The Clippers led in the International League in batting average (.285) and on-base percentage (.356) and have won two straight Triple-A titles.
Stearns, 60, was a four-time All-Star catcher for the Mets (1975-84) and has since worked as a coach and manager at all levels of professional baseball, including stints with the Yankees as their bullpen coach and Mets as their bench coach and third-base coach.
Wheelock will be in his 29th season as a coach in the Mariners organization, but first in a newly created position to oversee pitchers recovering from injuries. Prior to his work as pitching coach with Peoria from 2004-11, he was the club's Minor League roving pitching instructor. Wheelock was the first player ever to sign a contract with the Mariners after being the third pick in the 1976 expansion Draft. He pitched in the Majors with the Angels ('76) and Mariners ('77 and '80).
Azuaje has been in the Mariners organization the past five years. He'll head up the on-field instruction for the Mariners academies in Venezuela and the Dominican Republic.