That was the goal all along, though the club had yet to confirm anything before making the plan official.
Ramirez, whose 40th birthday coincides with the day of his scheduled A's debut, has been participating in extended spring training games in Arizona. Fans interested in seeing him in Sacramento will be able to do so May 25-28.
His addition to the big league lineup will create a difficult roster decision for the A's, who already have designated-hitter options in Seth Smith and Jonny Gomes. Neither is likely to be removed from the roster, given the way both have been swinging the bat, so it's possible a left-handed first baseman gets sent down. Daric Barton, who entered the day mired in a 1-for-20 slump, has options, while Kila Ka'aihue does not.
Smith and Gomes, meanwhile, will likely see sparse playing time come June, since left fielder Coco Crisp (inner ear infection) and center fielder Yoenis Cespedes (left hand) are expected back from the disabled list by then.