De La Rosa, who grew up in Santo Domingo, has known the Martinez brothers, Ramon Martinez and Pedro, since he was a child. His grandmother, he said Friday at the Red Sox rookie development camp at Harvard University, served as nanny to Ramon and Pedro when they were little, and he has kept in touch since.
And now, De La Rosa says matter-of-factly, he has mastered the Martinez changeup. If true, given he also has thrown a fastball clocked at 100 mph even after Tommy John surgery, De La Rosa might stir some of the similar excitement his idol did.
"He taught me the grip," said De La Rosa, who is listed at 5-foot-11 but is stockier than Martinez was at the same age, though he weighed just 130 pounds when the Dodgers signed him for $15,000. "I've learned how to throw it to both sides of the plate, to left-handed hitters and right-handed hitters. I really command the pitch. I can throw it inside to lefties.
"Ninety percent of my strikeouts come on my changeup. I throw the changeup at three different speeds -- 94 miles an hour, 88 and 78."