"I don't think it'll be much longer than [15 days], but it's hard to tell," Weiss said. "We're thinking at this point that will be sufficient, the 15 days. But with a pitcher you've got to build them back up a little bit. That'll be part of the process with Chatty."
Oberg was with the Rockies from April 25-May 20, posting a 4.76 ERA with six strikeouts and five walks in eight Major League outings spanning 11 1/3 innings. At Albuquerque, Oberg had a 2.89 ERA with 21 strikeouts against seven walks with five saves in six chances.
In Sunday's 3-0 loss, Oberg threw two scoreless innings, allowing two hits and striking out two.
The move might not be the end of the maneuvering. Righty Eddie Butler, who struggled after replacing Chatwood on Saturday, is in line to return to the rotation for the next turn. But the Rockies are left without a long reliever. Righty Jordan Lyles joined the Rockies on Sunday in Miami, but no roster move was announced.
Thomas Harding has covered the Rockies since 2000, and for MLB.com since 2002. Follow him on Twitter @harding_at_mlb, listen to podcasts and like his Facebook page. This story was not subject to the approval of Major League Baseball or its clubs.