Tatsuya Sato is a 27 year old right-handed reliever for the Orix Buffaloes that has emerged as one of the most effective relievers in the NPB despite taking a weird path to the Buffaloes.
The 5-10 169 reliever is definately undersized, and he didn't make his NPB debut until he was 26. After pitching in college, Sato went the industrial league route after some injuries, and wasn't drafted until he was 25 years old.
After a taste of the Ichi-gun in 2012 where he was successful, he has a 3.73 2013 kwERA with a 51 ERA -, third best in the entire Pacific League out of pitchers with at least 45 innings (Masahiro Tanaka and Takahiro Matsunaga). With that kind of effectiveness, he might be closing on many teams, but the Buffaloes already have the very talented Yoshihisa Hirano, so Sato is more of a setup man, with only 8 games finished.
In his delivery, Sato brings his leg up and back towards him. He doesn't actually turn his hip, so he is working against his delivery a bit, which may help explain his walk rate, which is a little high (but forgivable because of the strikeouts). He uses a pretty dramatic pause as well, mustering every bit of deception up he can. He seems to have cleaned up his head movement in his delivery some, which will help mechanically, and his landing and everything looks good. So other than the obvious fact that he has a lot going on in his delivery, enough that it may work against him in the sense of repeating, but obviously works for him in the sense of deception.
As a draft prospect, he got up to 91-94 MPH, but averaged in the 90 MPH range in 2012. It averaged 91.22 MPH in his final outing of the 2013 season (if he doesn't pitch in the two makeup games at the end of the season).
He can get whiffs high in the zone with the pitch, aggressively using it as a strikeout pitch. Flipping through his heatmaps on NPB Tracker from last year, it seems that he was a very high ball pitcher with the fastball. He may be a slight arm side pitcher, but it doesn't seem that there is a big difference between which side of the plate he throws it to.
Occasionally, he will throw a forkball, but the slider is used a lot more (he had cutter and curve according to draft report, but we haven't seen it in the NPB). The pitch will get up to 86-87 MPH, but averages about 81 MPH, so about normal considering his average fastball in 2012.
His platoon splits are a little odd, as he has a better K/BB against lefties, but a better average against and lower home run rate against righties. With his pitch selection (the slider usage especially), we would expect him to be better against righties. In the end, he will probably go wherever his slider takes him. His fastball will definitely work in the NPB, and as long as his slider is effective, he can change any hitter's, regardless of league quality, eye level.