Good things come to those who work, and Ryu is just getting started, building arm strength while waiting for his 91-94 mph heater and precise curveball to show up.
The first step is getting a grip, literally, on these baseballs.
"I have to get adjusted to the ball as quick as I can," Ryu said through an interpreter. "It's different -- especially the seams. The seams are very different. Balls are more slippery."
It behooves seamheads, who evaluate everything, and Dodgers management to reserve hard judgments until the big, good-natured left-hander gets his feet firmly planted on American soil.
Angels manager Mike Scioscia was impressed on Friday when Ryu was yielding four hits, including a two-run homer to Josh Hamilton, while striking out three in two innings at Tempe Diablo Stadium. Scioscia noted, with reservations, the talent that moved the Dodgers to win the bidding competition for the Korean League leader in strikeouts in five of his seven seasons.
"No doubt you can see the life in his arm," Scioscia said. "He can spin the ball and has a nice changeup to complement his fastball. The guys thought he was a little deceptive. He's got good stuff.
"Still, the challenge of being a starting pitcher in Major League Baseball goes a little deeper than his arm. How is he at pitch 100? Pitch 90? How will he handle 33 starts?"
Ryu pitched every sixth day in Korea. If he carves out a spot in the Dodgers' rotation -- no guarantees there -- he'll be going every fifth day.
Ryu has four pitches: fastball, changeup, curve and slider, in that order of preference. Those who watched him pitch for Korea in the 2009 World Baseball Classic and 2008 Olympics saw a big kid who worked off a fastball in the 93-94 mph range, up in the zone.
That heater wasn't visible in his second spring start, arriving in the high 80s. Maybe that's why he didn't seem comfortable bringing it inside.
Ryu wasn't aware that the first man he faced, Mike Trout, was arguably the best player in the game in 2012. Trout walked after fouling off one of Ryu's best changeups.
"Changeups, changeups," Trout said. "I saw a lot of changeups."
Two hitters later, Ryu wished he'd stayed with his change. Hamilton worked the count full and launched a slider -- the first one Ryu had thrown this spring -- over the wall in right-center.
Ryu, whose friendly manner and sense of humor have endeared him to everyone in Dodgers camp, was aware of Hamilton's reputation. Ryu said he "wanted to see how Josh would react" to the slider "but got too much of the plate."
Angels slugger Mark Trumbo said he got a look at all four of Ryu's deliveries and could envision his talent blossoming as his comfort zone increases.
"He definitely threw me everything," Trumbo said. "I got a change, a big curveball, a slider. I couldn't really judge the velocity on his fastball. I think he'll be good for them."
One advantage pitchers from distant places have been known to exploit is the lack of familiarity by American hitters.
Angels third-base prospect Luis Jimenez, an aggressive hitter who slashed a single against Ryu, had a different take on that.
"I didn't know him," Jimenez said, "but he didn't know me."
Dodgers manager Don Mattingly sees some of David Wells in Ryu, both physically and in pitching style and repertoire. While the Dodgers would like to see the 25-year-old Ryu seize one of those rotation roles, they have options.
Clayton Kershaw, Zack Greinke, Josh Beckett and Chad Billingsley, if healthy, are entrenched. Chris Capuano, Aaron Harang and Ted Lilly also are of proven quality.
Mattingly, who stayed in Glendale for Greinke's start on Friday, judged Ryu's effort, based on reports, "just OK."
Ryu, Mattingly added, "is a competitor for one of the five [starting] spots. Nobody's guaranteed anything in those spots. He controls his own destiny, and we'll see where it goes."
Ryu could open the season in the bullpen, continuing to adapt and build arm strength as a middle reliever.
One highlight of the spring for Ryu has been the tutorial sessions provided by Koufax, who suggested an adjustment with his thumb on the release of his curveball. But Ryu is mindful of his need to go with what feels right; facing big league hitters is not an ideal time to experiment.
"American hitters have better natural strength and bat speed," Ryu said, adding that Korean hitters are best known for their hand-eye coordination.
If he wasn't well-versed on Trout, Ryu was keenly aware of the legend of Koufax and was gratified to hear the great one endorse his mechanics during his visit to camp.
"He said my ball comes out easy," Ryu said. "I want to be like him."
Clearly, this is one smart southpaw.