De La Rosa comes to the Ducks with two seasons of Major League experience, both with the Arizona Diamondbacks. He went 2-1 with a 4.21 ERA and 48 strikeouts in 44 games during that span. In his big league debut on July 14, 2013, the Dominican Republic native threw two perfect innings against the Milwaukee Brewers. The following season, he compiled a 2-0 record with a 2.95 ERA in 25 appearances out of the bullpen.

The 26-year-old spent the 2015 season with the Padres, Athletics and Dodgers organizations, reaching the Triple-A level with all three. He combined to pitch in 49 games (one start) and totaled a 4-2 record with a 3.32 ERA, eight saves and 54 strikeouts. He previously was named an MiLB.com Organization All-Star with the Diamondbacks in 2012 and a Northwest League Post-Season All-Star in 2010. De La Rosa was originally signed as an amateur free agent by the Diamondbacks in 2008.