"We've been looking for a left-handed bat to call up when rosters expand," O'Dowd said Sunday. "If Jason is healthy, he's coming."
Giambi, 38, a former All-Star with 407 career home runs who was released by the Athletics on Aug. 7 after he slumped to .193 through 83 games, will play for Triple-A Colorado Springs to regain his swing, then join the Rockies when the roster expands to a limit of 40 on Sept. 1.
"This is a very good teammate, a guy who has been in the arena that we're in right now and gets that, which in my opinion is another helper with some of our younger players," Rockies manager Jim Tracy said. "We'll see where it all goes."
In addition, veteran right-hander Russ Ortiz, who began this season with the Astros and briefly pitched in Triple-A for the Yankees, joined the Colorado Springs club for Sunday's game against Reno and was scheduled to pitch in relief.
Ortiz, 35, gives the Rockies an experienced alternative, since they don't know how long they'll be without right-hander Aaron Cook (10-6), who went on the disabled list Saturday with a sore right shoulder. However, Ortiz might not come up immediately when rosters expand. O'Dowd said Colorado Springs is likely to make the Pacific Coast League playoffs, and Ortiz could stay with the Sky Sox for regular work beyond Sept. 1.
"Our guys had interest in him, and he's another depth guy to go to," O'Dowd said.
Thomas Harding is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.