Matt Herges was designated for assignment to clear a 40-man roster spot for Keppel.
He had thrown four innings over the last three days and the Rockies felt the need to bring up a fresh arm.
"In fairness to Matt maybe it was a little bit of him (being ineffective)," manager Clint Hurdle said. "But he's thrown a lot. He threw the last day he was in Colorado Springs, he threw an inning the first day he was (Thursday) and he threw yesterday. We need to fill some voids right now."Most importantly, Ramon Ramirez was placed on the 15-day DL with a sprained right elbow.
Ramirez, who's been effective as a seventh-inning reliever, injured his arm Tuesday night against the Giants. Ramirez was credited with a win in the Rockies' 5-3 victory. Ramirez's stint on the disabled list is retroactive to Wednesday, meaning he's eligible to return on May 3.