Ryan Sadowski has returned to the United States after 3 years in the KBO, signing a minor league deal with the San Francisco Giants. He spent the last three years with the Lotte Giants and (as noted in the KBO WAR article), he had a -.9 eWAA and .311 FIP WAA in 2012.
For his 3 year KBO career, he had a 5.16 eWAR and -1.28 eWAA. His career FIP was actually worse than his ERA in the KBO (4.21 to 4.03), which is a 4.249 FIP WAR (or about 1.4 WAR a season) and -2.19 FIP WAA. So he was a below average pitcher in the KBO according to the WAR metric. However, Lotte's ballpark is the most hitter friendly park in the KBO according to 2007-2011 park factors (for whatever reason, Google Docs doesn't really let me open that link in a new tab, if it does the same for you, I apologize). If we just use FIP (so we only really neutralize the HR part of the park. I don't really buy K/BB park factors unless there is some kind of weird batter's eye), we can subtract 8% of the homers Sadowski gave up and adjust his FIP to about 4.12, which would make his FIP WAA about -1.72 and FIP WAR about 4.72 for his 3 years in the KBO. The difference is minimal and his actual ERA in Lotte's home stadium (16 games, 85 innings) was 4.13 in 2012. He had an ERA of 6 in over 13 innings in KIA's stadium and Nexen's stadium. Combined, those parks are about neutral, so it has to do with randomness/Sadowski not pitching well/lineups. I find it hard to blame the park for Sadowski's struggles in the KBO, especially when his 2011 splits say that he was better at home as well.
In the Majors, he actually got to make 6 starts with the Giants (28.1 innings) in 2009 where he was about average according to ERA (0.0 WAA), but he walked as many batters as he struck out. He spent most of the year in AAA, where he struggled with a 5.11 FIP in 89.1 innings.
Sadowski was originally a 12th round pick of out of the University of Florida by the San Francisco Giants. Depending on which system of classification you trust (Fangraphs has him throwing less sinkers than Brooks), Sadowski was mainly a sinker/slider guy. He was a ground-ball guy in his short stint in the Majors, and had nearly 2 ground-balls per every flyball in 2012 with Lotte. The right-hander's velocity was below average in the Majors, sitting around 90 MPH on his 4-seamer. Again, depending on which system you believe, he either threw a lot of cutters or no cutters (basically, Brooks Baseball believes that his slider is a cutter). Sadowski evidently calls it a cutter, while others call it a slider (in seeing it, it does look more like a cutter to me).
He also threw an occasional changeup, but relied on the curveball as a pitch with 2 strikes or ahead in the count, especially against lefties. In 2012, he walked nearly as many right-handed batters as he struck out and was better against lefties. In 2011, the splits were just about the opposite, as he struggled against lefties and was better against righties.
According to his KBO Data scouting report, he throws a cutter, but mainly likes to throw it, along with the 4-seamer, early in the count (which is the opposite of his MLB stay, as he mainly threw his cutter/slider late, mainly against righties). The report also says that he throws a slider and a two-seamer. It says he throws the cutter at a high frequency (so this should be the pitch he threw in the majors) and the slider in a low frequency (along with a changeup in a low frequency). He also throws the sinker and the curve at a common frequency according to the report.
In watching video of him from his time in the KBO, the tall, somewhat lanky pitcher threw a lot of sinkers that almost flutter and move arm side in the 89-91 MPH range. His delivery looks like a delivery that you often see in Korea, as there are a lot of legs are arms coming at the hitter via a high leg kick. This delivery is at least somewhat different (though he did come at hitters with a lot of legs and arms) than his MLB days, as it seems he is now coming a little less over the top and the overall motion seems much more fluid. He also begins his motion by almost rocking back and forth, something he didnt do in the Majors, and something that seems to get his delivery working more fluidly. Since he is not a hard thrower, he has to make up for it with movement, and basically everything he throws moves pretty well. However, as the walk rates suggest, he doesn't exactly have good command/control.
I fully expect to see Sadowski pitching in the PCL this year, as I don't think he will be very helpful at the Major League level. The deception and ability to mix pitches may lead to a good minor league season, but it is hard to see him overcoming the lack of stuff and consistency to pitch well in the Majors in 2012.