Wei-Yin Chen’s semi-secret (and valuable) skills

Wei-Yin Chen just got a contract that could bring him just shy of nine figures by the time he’s done. If he doesn’t opt out, and the sixth year vests, he gets $96 million.

Here are some other facts about the new Marlins’ lefty. By strikeout rate, he’s 79th out of 132 qualified starters over the last three years. He’s 112th in home runs per nine innings over that same time frame. He’s no sinkerballer that gets by on worm-burning ground balls, either: He’s 110th in ground balls since 2013 began.

But there are a few spots where Chen rates much more highly. And it’s because he sits atop those leaderboards that makes him a good value signing for the Marlins, even at what seems like a hefty price to some.


Chen doesn’t walk batters. He’s 20th of 132 in that statistic over the last three years, and he’s actually improved the last few years as he’s gotten to know the strike zone here. He’s tenth since 2014 began.

Of course, walk rate is not all command. Sometimes pitchers throw the ball outside the zone on purpose, after all. But there are other ways to try and measure the ability to repeat pitches.

One way is to look at breaking balls in counts where the pitcher is looking for a swing as I did for this year’s Hardball Times Annual. In counts like 2-1 and 1-1, batters are looking for a pitch to hit, and that’s the time to bury a breaking ball and get a swing and miss. “The well-commanded breaking ball comes out in the 2-1 count, makes the hitter think fastball, and then bottom drops out,” according to Dodgers starter Brandon McCarthy.

If you judge Chen’s command by his ability to keep his curve low in the zone in those counts, he does well. Only Zach Duke and Will Harris threw more than 50 curves over the last three years in those counts and have kept the ball lower on average.

Another way to look at command is to look at the ability of a pitcher to hit the strike zone in a three balls and no strikes count, when all they want to do is get the free strike. Chen is 32nd out of 111 qualified pitchers over the last three years in that statistic. By all accounts, he can command the ball.

Soft Contact

Sort the FanGraphs leaderboards for soft contact, and you’ll find Chen 36th out of 132 qualified pitchers over the last three years. It gets more impressive if you actually look at the last two years, once again — he’s 17th in Soft% since 2014 started.

Soft contact is judged by human eyes, by someone watching the game. Maybe a better judge is the Statcast system, put in place this last year in all ballparks to judge more advanced statistics. By exit velocity on balls in play, Chen did very well last year — by BaseballSavant.com, he was 25th with an average of 87.6 mph, right between Jacob deGrom and Carlos Martinez.

But even that measure isn’t complete without one more piece of information. A softly hit ball at the right angle can still be a hit. Which brings us to Chen’s last, best skill.

The Pop-Up

There’s a way that Chen uses his command to get that weak contact. His fastball has an inch more rise than the average four-seamer, meaning it falls an inch less than batters expect it to, due to backspin mostly. That movement, plus where he puts it, elicits pop-ups. Look at where Chen throws his fastball to right-handed hitters.


That’s a lot of high and tight for a fastball. Joey Votto once told me about the pitch that creates the pop-up: “It’s got to be the perfect sliver of the strike zone, up and in-ish, and I have to take the wrong swing, and I have to swing at it.”

And so we get to Chen’s best spot on any leaderboard: He’s fifth in baseball in pop-up percentage since 2013, right behind Marco Estrada, Hector Santiago, Max Scherzer, and Trevor Bauer. At 5.6%, he’s almost two standard deviations above the mean (3.2%), so he’s good at what he does.

The pop-up is an automatic out. If you add it to the other automatic out, the strikeout, and subtract the only other automatic play that a pitcher can influence all by himself — the walk — you get a good measure of a pitcher’s quality. Here, then, are the top 30 pitchers since 2013 in strikeouts plus pop-ups minus walks.

Strikeouts and Pop-ups Minus Walks Leaders
Name K% BB% PU% KPU-BB%
Max Scherzer 30.7% 3.8% 5.9% 32.8%
Clayton Kershaw 33.8% 4.7% 2.7% 31.8%
Chris Sale 32.1% 4.9% 3.5% 30.7%
Madison Bumgarner 26.9% 4.5% 4.3% 26.7%
Carlos Carrasco 29.6% 5.9% 2.0% 25.7%
Corey Kluber 27.7% 5.1% 2.8% 25.4%
Jacob deGrom 27.3% 5.1% 3.1% 25.3%
Chris Archer 29.0% 7.6% 2.6% 24.0%
David Price 25.3% 5.3% 4.0% 24.0%
Jake Arrieta 27.1% 5.5% 2.1% 23.7%
Matt Harvey 24.9% 4.9% 3.5% 23.5%
Zack Greinke 23.7% 4.7% 3.1% 22.1%
Jon Lester 25.0% 5.7% 2.5% 21.8%
Cole Hamels 24.4% 7.1% 3.8% 21.1%
Danny Salazar 25.8% 7.0% 2.2% 21.0%
Gerrit Cole 24.3% 5.3% 1.8% 20.8%
Mike Fiers 23.7% 8.4% 5.3% 20.6%
Dallas Keuchel 23.7% 5.6% 2.4% 20.5%
Taijuan Walker 22.2% 5.7% 3.9% 20.4%
Ian Kennedy 24.4% 7.3% 3.0% 20.1%
Jason Hammel 24.2% 5.6% 1.5% 20.1%
Francisco Liriano 26.5% 9.1% 2.5% 19.9%
Wei-Yin Chen 19.3% 5.2% 5.5% 19.6%
Jordan Zimmermann 19.7% 4.7% 4.5% 19.5%
Johnny Cueto 20.3% 5.3% 4.3% 19.3%
PU% = IFFB% * FB%
PU% has a .67 year to year correlation

Suddenly, Wei-Yin Chen is a top-25 starter. He doesn’t have the velocity or strikeout rates of an ace, and he’s not an upper-tier ace even on this final leaderboard.

But there he is, a rank above Jordan Zimmermann, a pitcher who just this season cost millions more. Given that more of Chen’s long fly balls will die in the park this season in Miami, and he’s demonstrated the ability to limit the walks, coax the pop-up, and strike out just enough guys to be a force in a tougher park and a tougher league, maybe the Marlins actually got a steal with their big signing.

With a phone full of pictures of pitchers' fingers, strange beers, and his two toddler sons, Eno Sarris can be found at the ballpark or a brewery most days. Read him here, writing about the A's or Giants at The Athletic, or about beer at October. Follow him on Twitter @enosarris if you can handle the sandwiches and inanity.

One Response to “Wei-Yin Chen’s semi-secret (and valuable) skills”

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  1. triple_r says:
    FanGraphs Supporting Member

    For all of that soft contact, though, he still hasn’t put up a decent BABIP: In that 132-man sample, his .296 ranks just 68th. Where he’s excelled is preventing runners from scoring — his 78.1 percent strand rate in that span finishes sixth, only behind Zack Greinke, Yu Darvish, Clayton Kershaw, Alex Cobb, and Johnny Cueto. I think the latter ability will serve him better in Miami than will the former.