Yoo Hee-kwan (or Yu Heui-Kwan) was one of the KBO pitchers that statistically rated out as a possible MLB prospect, at least going by 2013's statistics. Yoo threw 145.1 innings in 2013, posting a 3.53 ERA and 3.58 FIP. This had to be one of the biggest surprises of the Korea Baseball Organization season, as he had just 16 innings under his belt in the KBO before the year started, and hadn't pitched with Doosan since 2010. Yoo also made two starts in the first round of the playoffs against the Nexen Heroes, striking out nearly a guy an inning, and giving up just 1 run. The 27 year old left-hander burst on to the scene rather suddenly, so he doesn't have a Naver scouting report. Standing under 6 feet, Yoo isn't the prototypical starting pitcher, which may be one of the reasons he was a late bloomer. As we will see below, he also isn't a traditional power pitcher.
First, however, let's take a look at his mechanics, starting with a side view
The following GIF is Yoo throwing a fastball by the best hitter in the KBO, Park Byung-ho
He would pitch inside to right-handers at times despite the velocity, and as you can see above, was effective at doing so. Many times to left-handers he was trying to get the fastball outside and would basically fall off the mound, overcompensating to get the ball glove side.
The change and the slider sometimes tended to blend, at about 74-75 MPH it would go inside and low to right-handed batters, sometimes looking like a weird 2-seamer.
Obviously the fastball velocity alone limits him from being a MLB prospect, and it helps explain why it took this long for him to get his first chance in the KBO, but with that said, there is a good mix of pitches and deception here, enough that he should be effective in the KBO in coming years. Yoo probably won't continue to pitch at the same level as he did in 2013 as hitters begin to have more opportunities to adjust to him, but he should still be an above average starter in the league just because of his pitchability.