As part of the Seattle Mariners’ 50 Seasons Celebration, the team has announced the first-ever Mariners Alumni Home Run Derby, which will take place after the Friday, Aug. 7 game against the Rays on at T-Mobile Park. Ken Griffey Jr., a two-time MLB Home Run Derby champion, will serve as commissioner for the alumni derby. The Seattle Mariners’ top AL West competition is changing Nelson Cruz and Jay Buhner will captain teams made up of former Mariners.