De La Rosa, who turned 34 on April 5, suffered a left groin strain in Spring Training. He made two rehab starts for Triple-A Albuquerque on April 9 and April 14. Last season, he tied a career-high with 32 starts, going 14-11 with a 4.10 ERA (184.1 IP, 84 ER). He enters 2015 ranked second in franchise history in wins (69), third in strikeouts (743) and fourth in starts (150) and innings pitched (858.1). De La Rosa also owns a career mark of 45-14 at Coors Field, the best winning percentage and the most wins in franchise history.
Oberg, who turned 25 on March 13, was called up to the Rockies on April 12 and made three appearances. He made his first Major League appearance and collected his first win on April 14. The Rockies selected him in the 15th round of the 2012 First-Year Player Draft.