Semien will start at shortstop and lead off Sunday against the Mariners, Greg Johns of MLB.com reports.

EDGE Analysis

Semien has regularly been serving as the Athletics' table setter against left-handed pitching, but the leadoff assignment in the series finale is more notable with right-hander Felix Hernandez on the mound for Seattle. Nick Martini has been the Athletics' primary option atop the order of late versus righties, but since he was optioned to Triple-A Nashville a few days earlier, it looks like those duties could now fall to Semien. Though he's fared better versus southpaws this season with a 112 wRC+, Semien has at least hit a palatable .263 in his matchups against right-handed pitching.