Yastrzemski is not in the lineup for Sunday's game against the Orioles, Maria I. Guardado of MLB.com reports.
Yastrzemski receives most of his off days against left-handed pitchers, but he's sitting Sunday with righty Tyler Wells on the mound for Baltimore. The veteran outfielder has hits in nine of his past 10 games and has a .949 OPS during that stretch, so it's likely just a maintenance day. Blake Sabol, Austin Slater and Mitch Haniger will start from left to right in the outfield.