Oberg, the Rockies' No. 24 overall prospect, got the news before his game Saturday and caught a 6:30 a.m. flight Sunday to suit up in time for the series finale with the Cubs. Luckily his wife and his parents were visiting Albuquerque from the East Coast, and they were able to drive up to Denver on Sunday to catch Oberg's first game in purple pinstripes.
"There's great makeup with this kid, that's the thing that always gets communicated whenever we talk about him," manager Walt Weiss said Sunday. "Good stuff, plus stuff. Mid-90s with a good breaking ball. Good competitor. Lot of poise. He's an impressive kid."
Oberg's reputation has been built around a great curve and an intimidating fastball, but he's been working to augment that one-two punch while in the Rockies' Minor League system.
"My changeup's gotten better over the last three years," Oberg said. "And then a slider I've been working on last year and into this year. I think they just wanted a more controllable off-speed pitch, but they don't want me to get away from the curveball."
Oberg is fortunate to have former Rockies reliever Darren Holmes joining the Rockies coaching staff, and he's picked Holmes' brain as a pitcher who had great success with his curve in Colorado.
"I've had a few conversations about that with Darren," Oberg said. "His thing is just making sure that you adjust your eyesight and adjust your target. He said other than that, you still can throw it here. Just make sure you have the proper target."
Oberg played a season of Rookie ball at altitude in Grand Junction, Colo., and he pitched the season's second game in Albuquerque.
"It'll be exciting for him, make his Major League debut," Weiss said. "We're looking forward to watching him pitch."
Axford could be on the Family Medical Emergency List for three to seven days.
Owen Perkins is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.