SCOTTSDALE, Ariz. -- Working on new pitches, or improving old ones, is a time-honored Spring Training tradition for pitchers. The Dodgers in general, and Hyun-Jin Ryu in particular, are putting a spin on it.
Although his two-seam fastball remains the top priority, Ryu this spring is trying to tighten the spin of his deep-count curveball and provide a different look to hitters than the one he's been using since turning pro in Korea in 2006. He spun several in his Cactus League debut on Sunday in the Dodgers' 13-7 win over the Rockies.
At Camelback Ranch in Glendale, the Dodgers often set up a device behind the catcher that tracks spin rates, angles and velocity for real-time monitoring by coaches and players, viewed on a tablet stationed on a tripod behind the mound.
According to Statcast™, Ryu's curve spin rate last year was 2,422 rpm, basically Major League average (2,490). That said, he was more effective than average with it. Hitters had a .145 average and .309 slugging percentage against it. The average was tied for 10th-lowest among the 120 pitchers who had at least 50 at-bats decided on curveballs in 2017.
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Hitters swung and missed on 43 percent of Ryu's curves, ranking 18th of 104 pitchers who had at least 100 swings against their curveball last year. But only three of Ryu's 116 strikeouts came on the curve.
Pitching coach Rick Honeycutt said the desire is to develop a tighter curve to use later in counts that can deceive the hitter with the look of a fastball early and a sharper break later.
Ryu tried the new curve on Sunday and was disappointed at bouncing several, but Statcast™ confirmed an improvement. His average spin rate on seven curves was 2,551 rpm (ranging from 2,432 rpm to 2,701 rpm), up from that 2,422 rpm he averaged last year. 
The 2,551 rpm is higher than he averaged in any game last year, and his 2,701 rpm max -- the curve that struck out David Dahl in the second inning -- is a higher spin than any individual curve he threw last year.
Ryu was charged with four runs in 2 2/3 innings on Sunday, walking two and striking out two. One of those hits was a Chris Iannetta two-run home run, which came on a changeup. Ryu wasn't happy with his tempo, which was the focus of an additional inning thrown in the bullpen.
"I thought he was OK," manager Dave Roberts said of Ryu. "There were some misfires where he couldn't put hitters away. Velocity was OK. It was a good day of work and we expect him to just tick up."
The Statcast™ Visualizer notes that Ryu's curveball comes out of his hand more distinctly than his other pitches, making it less deceptive.

Zach Crizer of Baseball Prospectus found that Ryu's release and pre-decision point distances are larger than average, and his fastball and curveball end up farther apart at the plate than average.

David Adler, Matt Kelly and Daniel Kramer of MLB.com contributed to this story.