Forecast for Masahiro Tanaka? Depends on the computer program

Yankees pitcher Masahiro Tanaka throws in the bullpen

Yankees pitcher Masahiro Tanaka throws in the bullpen on the morning of Tuesday, Feb. 18, 2014. (Credit: Newsday / Thomas A. Ferrara)

By now you're probably well aware of the video game-like statistics that Masahiro Tanaka posted during his final season in Japan.

Pitching for the Rakuten Golden Eagles, he went undefeated, winning 24 of his 27 starts with a 1.27 ERA and 0.94 WHIP. He allowed only six home runs and walked only 32 in 212 innings.

So Francisco Cervelli might as well have been speaking for Yankees fans everywhere earlier this month when the catcher expressed how excited he was to be behind the plate for Tanaka's first bullpen session of spring training.

"When you see those kind of numbers," he said, "that's ridiculous."

But let's say -- for argument's sake -- that Tanaka was coming off a season in which he went 16-8 with a 3.40 ERA, having given up 17 homers and allowed 41 walks in 193 innings.

Those are very solid numbers, good enough to be placed at the start of any team's rotation. But no one would describe them as "ridiculous" statistics.

Yet according to a computer program developed by ESPN writer Dan Szymborski, that's the type of statistical season that Tanaka's impressive 2013 campaign in Japan translates to had he been pitching against major-leaguers in a neutral park.

In 2012, Tanaka posted a 1.87 ERA in Japan. Szymborski said his system ("ZiPS") translated that into a 4.09 ERA had he been pitching here.

So you can understand why Yankees general manager Brian Cashman repeatedly, and admittedly, has been trying to lower the baseball world's expectations for his newly acquired righthander. The chances of the 25-year-old producing anything near what he's done in Japan lately are mighty slim.

It's no secret that the overall competition in Japan is not at the level of the major leagues. But nowadays, thanks to the rise of advanced metrics on nearly all levels of the game, we have a better statistical sense of just how the play in Japan compares.

"It's above Triple-A but below the majors," Szymborski said. "It's a little closer to Triple-A than to the majors."

By extension, that means we perhaps have a better sense of what to expect from players when they make the jump, based on what they've done previously in Japan.

Brian Cartwright is a photogrammetrist by day and baseball statistical analyst by night. Like Szymborski, he has developed his own statistical predictor program ("Oliver") and has been constantly tweaking how it projects Japanese players who make the jump.

"Basically, it's a process at looking how the player did in two environments and comparing the results," Cartwright said, "and doing it for a group of players."

Of the most widely cited statistical projector programs, Cartwright's program (available on fangraphs.com) is easily the most optimistic when it comes to predicting how well Tanaka will perform for the Yankees this season.

His program sees Tanaka going 17-6 with a 2.59 ERA and 1.01 WHIP, allowing 15 home runs and striking out 193 in 205 innings.

Cartwright recalled that he was criticized by some for his program's aggressive prediction for Yu Darvish two years ago. He projected a 2.57 ERA, a 0.97 WHIP and 2.0 walks and 9.6 strikeouts per nine innings.

In two seasons, Darvish has pitched to a 3.34 ERA, 1.17 WHIP and 3.8 walks and 11.2 strikeouts per nine innings.

So although his predictions for Darvish proved to be optimistic, they weren't insanely so.

Then there's the predictor tool called "Steamers," which also is listed on fangraphs.com. This program was created six years ago by a Brooklyn high school teacher named Jared Cross and two students who wanted to win their fantasy league.

Their program is the most conservative when it comes to Tanaka, foretelling a debut season in which the righthander goes 13-11 with a 3.71 ERA and 1.18 WHIP, allows 21 home runs and strikes out only 156 in 192 innings.

The strikeout rate in the majors has been on the rise in recent years, but Cross said their program doesn't yet give Japanese pitchers coming over the extra bump in strikeouts. They may be compelled to change that, though, especially after seeing Darvish lead the majors last season.

"I'm definitely excited to see how Tanaka does in comparison to the projection," Cross said. "Sometimes I get into a space where I root for the projection."

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