The deal is worth $25 million, according to multiple media reports. It is pending league approval.
De La Rosa was set to become a free agent at the end of this season after the Rockies exercised their club option for 2014 and he exercised his player option for 2013. The left-hander originally signed a $21.5 million, two-year contract in December 2010.
De La Rosa, 33, has gone 13-10 with a 4.26 ERA in 28 starts this season. With Jhoulys Chacin sidelined, De La Rosa received his first Opening Day assignment after going a career-best 16-6 with a 3.49 ERA last season.
The lefty was expected to be the Rockies' ace in 2011 before tearing an elbow ligament that May. He was out most of that season and the next following elbow surgery and a subsequent setback in his rehabilitation.
Information from The Associated Press was used in this report.