"He was our hottest hitter for a while and has slowed down some," said manager Bob Melvin. "He wasn't going to keep the pace he was at, but usually he squares up some balls and has some better at-bats. He's just struggling right now."
Making the start at third base on Thursday while Josh Donaldson acted as designated hitter, Callaspo drew a walk in his first plate appearance but finished 0-for-3, extending his hitless streak to 12 at-bats.
Callaspo is just 6-for-42 (.143) in May, after batting .269 in April. He has grounded into a double play in two of the last four games and has hit into 10 on the season, which is tied for the Major League lead.
Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.