Jeffers is out of the lineup for Friday's game against Oakland.
Jeffers has yet to make consecutive starts behind the plate this season, and his playing time has slipped lately, as he hasn't made a start at designated hitter since June 1. It's been a rough month so far for the 27-year-old, who has gone 3-for-30 through nine contests. Christian Vazquez will step in behind the plate Friday to catch for Simeon Woods Richardson.