The Rockies reinstated Diaz (calf) from the 10-day injured list Sunday. He'll serve as the Rockies' designated hitter and will bat fifth in Sunday's series finale versus the White Sox, according to Luke Zahlmann of The Denver Gazette.
Colorado designated infielder Elehuris Montero for assignment to clear room on the active roster for Diaz, who returns to action after missing just under three weeks with a left calf strain. Though he'll operate as the Rockies' DH in his first game back, Diaz should soon settle back into primary duties at catcher, leaving fewer opportunities to go around for Jacob Stallings and Hunter Goodman.