Who is Wei- Yin Chen?

The Baltimore Orioles’ rotation was a disaster in 2011, ranking dead last in the major leagues in innings pitched, ERA and FIP as highly-touted young arms like Brian Matusz and Chris Tillman crashed and burned. The O’s and new GM Dan Duquette signed Japanese starter Tsuyoshi Wada last month, and now they’re looking to the Far East for another lefty in hopes of improving those dismal numbers in 2012, signing Wei- Yin Chen of Nippon Professional Baseball to a three-year contract.

Born in Taiwan, Chen pitched the past four years for the Japanese Central League’s Chunichi Dragons but had an opt-out clause in his contract that allowed him to become a free agent at age 26. Now that he’s coming stateside, what can we expect from Chen? Let’s take a closer look at his stuff and stats.

Chen has more of a drop-and-drive delivery commonly seen in the majors, as opposed to the hesitation present in the motion of pitchers like Daisuke Matsuzaka and Hiroki Kuroda. At his best, Chen has reportedly sat in the low-90s with his fastball while mixing in mid-80s sliders and forkballs and some slower curveballs. ESPN’s Keith Law ranked Chen 19th on his top 50 free agents list, saying Chen “offers more upside than the typical NPB refugee, both due to age and the chance for the slider to become a consistently plus pitch.”

While Chen is young and has a promising fastball/slider combo, his stuff was down in 2011. Pitch data from Patrick Newman’s NBP Tracker website shows that Chen’s heater sat in the upper-80s until around July, at which point he gained some zip and more often sat in the low-90s. His slider didn’t seem to recover as quickly, as the pitch sat in the high-70s for most of the year.

Chen apparently dealt with a leg injury in 2011, which could explain his velocity dip. Whatever the cause, this past year was his worst in Nippon Professional Baseball. I found Chen’s 2008-2011 stats from Baseball-Reference and then compared them to the league averages for each season. It’s always good to provide context, but this is especially important because NPB switched to a smaller, smoother baseball in 2011 that put a huge dent in offensive production.

Teams scored between 3.9 and 4.3 runs per game from 2008-2010, but just 3.15 runs in 2011. That means there’s a higher threshold for pitchers to truly stand out, and numbers that might have looked good in past years are run-of-the-mill in last year’s run environment. To account for that, I put Chen’s strikeouts, walks, home runs and ERA on a scale where 100 is average and above 100 means the pitcher was better than the league average.

Chen appears to have become a markedly different pitcher since he debuted at age 22, cutting his walks considerably and being stingy with home runs but also seeing his K rate plummet to way below the league average (26 percent below in 2011). The result was an ERA that was a modest 14 percent better than that of the average Japanese Central League pitcher:

Wei- Yin Chen’s Japan Central League Stats
Year IP K/9+ BB/9+ HR/9+ ERA+
2008 114.2 125 96 180 129
2009 164 118 123 180 231
2010 188 107 130 100 144
2011 164.2 74 159 120 114

Chen’s fantasy value is hard to gauge. He would have garnered much more interest a couple of years ago, when he sported a power fastball/slider arsenal and did a good job of both missing bats and limiting walks. Now, he looks more like an extreme control pitcher with a less-sinister repertoire. That’s not to say that Chen can’t regain his lost stuff and start striking out hitters again (his fastball velocity did creep back up late in 2011), but that four-year K decline isn’t a positive sign.

While we implore people not to take spring training performance as gospel (small sample sizes and drastically different levels of competition make the numbers fuzzy at best, useless at worst), you’ll have to do your homework on Chen to get a better read on his value. Do his fastball and slider look sharp? Do hitters have a hard time picking up his motion? Is he guaranteed a starting spot? Don’t write him off if he gets crushed for a 6.00 ERA in Grapefruit League action or start thinking he’s an ace if he puts up a 1.00 ERA, but it’s important to keep up with Chen’s performance and see whether his stuff has recovered. The 2011 version of Chen won’t help you, but the 2008-2010 version could.

A recent graduate of Duquesne University, David Golebiewski is a contributing writer for Fangraphs, The Pittsburgh Sports Report and Baseball Analytics. His work for Inside Edge Scouting Services has appeared on ESPN.com and Yahoo.com, and he was a fantasy baseball columnist for Rotoworld from 2009-2010. He recently contributed an article on Mike Stanton's slugging to The Hardball Times Annual 2012. Contact David at david.golebiewski@gmail.com and check out his work at Journalist For Hire.

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I used to follow the NPL closely and from what I read in the Japanese sports news, he was mentioned as a victim of the new baseball(touitukyuu) by a pitching coach(from his own team I believe?) because he could not get a good hold of the smaller baseball and thus unable to drive the ball towards the plate, suffering in loss of not only velocity, but also life in his fastball. He used to have a poor-man-Kershaw fastball.