Rooker won't play in Wednesday's game against the Brewers due to knee soreness, Martin Gallegos of MLB.com reports.
Manager Mark Kotsay said the team will wait to see how Rooker feels leading up to Friday's game against the Rockies before deciding whether he needs to spend time on the injured list. Carlos Cortes will work as the Athletics' designated hitter Wednesday while Lawrence Butler starts in right field, and that could be the defensive alignment the team uses if Rooker has to miss more time.