Diaz is out of the lineup for Monday's game in Pittsburgh.
Diaz had started in five of the past six games, going hitless in 16 at-bats over that stretch to drop his season-long batting average down to .179. Though he's one of the highest-paid players on the Athletics in the first season of a two-year, $14.5 million deal, Diaz may nonetheless find himself on the bench more frequently in the near future given his wretched start to his tenure in Oakland.