Diaz will be the opener for Saturday's game against Oakland, Susan Slusser of the San Francisco Chronicle reports.
This will be Diaz's third time appearing as an opener in a span of less than a week, as he filled the role Sunday against the Angels and Tuesday against the Dodgers. He threw 1.2 scoreless innings across those two appearances, so he's unlikely to last long before turning the ball over to a bulk reliever, a role which is expected to be filled by Joey Wentz.