One of the more intriguing signings this winter, the Dodgers handed Hyun-Jin Ryu $36M over six seasons. The 26-year-old South Korean lefty was thrust directly into the rotation, which has looked to be a great move so far. In his first two starts, he's allowed five runs in 12 2/3 innings, walking two and striking out 11 so far. His stuff is decent, but his polish is where he makes his living.
He looks to have both types of fastballs, throwing a four-seamer more. At 90-92 with decent life, his primary fastball has been knocked around so far, allowing a .400 AVG and a homer, only getting one whiff in 25 swings. The two-seamer has only 2.5 inches more tail and an inch more sink, a pitch I don't see getting much use over the season.
His changeup was touted as his best off-speed pitch, and it's been alright so far this year, getting eight whiffs out of 29 swings. At 80-82, the pitch has an average amount of fade with below-average depth. He is not the only pitcher with an effective changeup without great movement (Cole Hamels, Jered Weaver, Johan Santana,...), as arm speed is just as important as movement.
He has two breaking balls that he uses about 10% of the time each. His slider sits at 83-85, his main weapon against lefties. It has average movement, but there have been 7 whiffs out of 14 swings on the pitch. His curveball is a looper, averaging 69-71 without much sweep. It is not meant to be a game-changing pitch, but just one to change eye level and slow the bats down a bit.
After only 50 batters faced and 35 batted balls, it is too early to make any conclusions about his current peripherals. Based on his stuff, I'd expect a figure right around 20%, just a bit lower than his current mark. His 4% walk rate should go up, as his first-pitch strike percentage and Zone% have been right around average. He's also induced more groundballs than flyballs, though his stuff looks to be more flyball-heavy. Overall, it looks like that works out to be around league average.
Right now, Ryu looks like a solid investment for the present and future. He is listed at 6'2", 255, so that is not a good sign for someone that young, but if he keeps his weight at a manageable level, he should not suffer an extraordinary amount of injuries. For an unproven commodity out of the Korea Baseball Organization, Ryu has worked out well so far, showing the stuff and polish to maintain good performance for years to come.