The Athletics placed Hernaiz on the 10-day injured list Wednesday with a left ankle injury.
Hernaiz suffered the injury during Tuesday's 15-8 loss to the Rangers when he stepped awkwardly on first base while trying to beat out an infield hit. It's not clear at this point how long he might be sidelined. Max Schuemann and Brett Harris could handle shortstop for the Athletics while Hernaiz is out.