After elbow surgery, Danny Duffy abandoned his curveball. It’s back ... and so is he

Kansas City Royals starting pitcher Danny Duffy throws against the Chicago White Sox during the first inning of a baseball game Saturday, July 14, 2018, in Chicago.
Kansas City Royals starting pitcher Danny Duffy throws against the Chicago White Sox during the first inning of a baseball game Saturday, July 14, 2018, in Chicago. AP

The hesitancy derived from fear, Royals left-hander Danny Duffy nervous about another setback. Dating back to his days as a high school pitcher, a curveball was his out-pitch, a go-to weapon with a game on the line.

But a few years ago, he abandoned it. Threw it less than once per every 100 pitches.

He blamed the pitch for his Tommy John surgery in 2012, an injury to his throwing elbow that came just as he thought he was figuring out his way in the big leagues. So his solution? Get rid of it.

“I was afraid to throw it, man,” Duffy said. “That was the pitch that ultimately blew out my elbow. It was a mental block a little bit.”

In a perfect world, the pitch would have remained absent from his repertoire forever. He never planned to use it again. Hoped he would never need to use it again.

The most turbulent season of his career prompted him to face his fear. Nearly three months ago, as the life on the pitch remained part of his bullpen sessions, Duffy was searching for something to change his fortune. He turned to a reliable companion.

The curveball.

It’s revitalized his 2018 season. Duffy prolonged his return to form Saturday, throwing seven shutout innings in a 5-0 victory against the White Sox. In his past 10 starts, Duffy has a 2.73 earned run average. He has allowed one run or fewer in seven of those 10 starts.

The answer, he said, lies within the pitch he first learned in high school.

“The curveball has been a godsend,” he said. “What I was doing wasn’t working. So I tried to figure something new out. This isn’t so new as it is just trying to rekindle what I had when I first came up.”

The proof is in the statistics. According to Brooks Baseball, Duffy threw the curveball less than 2 percent of the time from 2015-17 combined, including less than once every 100 pitches in 2016 and 2017, and he had similar usage rates over the initial two months of 2018.

It’s back in full force over the last several weeks. It accounted for 8.9 percent of his pitches in June, and that number has soared to 19 percent in July.

Hitters can’t identify it, either. Well, or they can’t hit it, at least. Even before Saturday’s gem, opposing hitters were batting only .100 against Duffy’s curveball — making it far and away his most effective pitch.

“I’m just throwing it like I did when I was in high school,” Duffy said. Royals pitching coach “Cal (Eldred) has been able to refine it a little bit. It’s been good for me, man. Obviously I was absolutely atrocious the first part of the year. We’re starting to climb the mountain of being able to get back to where we were when we were successful.”

Ten starts into the season, Duffy was 1-6. His ERA stood at 6.88. His slider was being hit harder than normal, and Duffy worried he was tipping the pitch. Eldred and manager Ned Yost urged Duffy to stick with his fastball at a higher rate, and Yost believes that has made all of his off-speed pitches more valuable.

The curveball added another layer to the midseason overhaul, though it wasn’t as unfamiliar as it might appear. Even while throwing it so rarely from 2015-17, Duffy continued to mix it into his bullpen sessions between starts, thinking it might prove beneficial one day.

That day has arrived.

“I just haven’t needed it the last few years, and I haven’t necessarily wanted to need it,” Duffy said. “Until now.”