Hernaiz will start at third base and bat eighth in Wednesday's game against the Mets, Martin Gallegos of MLB.com reports.
Hernaiz is emerging as Athletics manager Mark Kotsay's preferred choice at the hot corner, having started at the position four times in a five-game span. The 23-year-old has posted a poor .561 OPS in August since being reinstated from the 60-day injured list Aug. 4, although that's better than what Abraham Toro (.345 OPS) has provided so far this month.