Hisashi Iwakuma's One Question Left

With apologies to Dave, I am also here to observe that Hisashi Iwakuma as a starting pitcher has been all right. Last night, Iwakuma started for the eighth time, and for the sixth time, he allowed three or fewer runs. More specifically, he allowed one run, which he has now done three times. Where Iwakuma used to be the 2012 Mariners' version of the 2011 Mariners' Jeff Gray, a guy who would play only imaginary baseball with ghost runners and ghost hitters and ghost friends, now Iwakuma's getting regular turns and he even has Eric Wedge's support. Not long ago Wedge stated that he thought Iwakuma deserved to remain in the rotation, on account of his performance.

There's an interesting thing that happens when you take all the American League starting pitchers and sort them by xFIP. I understand that I might be the only person in the world who would find this interesting, but, given a minimum of 40 innings, 86 AL starters qualify. Hiroki Kuroda ranks 15th in xFIP. Hisashi Iwakuma ranks 16th. Yu Darvish ranks 17th. They're all between 3.70 and 3.82. Get it? They're all Japanese! Wow! I'm going to leave this paragraph now and start another one.

Iwakuma's going to get more starts between now and the end of the season, and over the course of those starts we'll learn more about him, surely. At this point the Mariners might be considering re-signing him for 2013, but they'll let the season play out, and Iwakuma will also let the season play out. No point in making a decision right now, with still another month and a half.

But based on what Iwakuma's done to date, he's answered most of the questions. Iwakuma signed with the Mariners to a low contract, in large part due to concerns about his shoulder, but he averaged 90.4 miles per hour on his fastball out of the bullpen, and he's been around 90.6 miles per hour on his fastball as a starter. Iwakuma's velocity is where it was when he was healthy in Japan, and if he's been experiencing any discomfort, we haven't heard about it or seen evidence of it. Iwakuma passed his tests, and he's been pitching like a guy for whom nothing has changed since.

Iwakuma's demonstrated that he can pitch to righties, and that he can pitch to lefties. He's demonstrated that he can generate grounders, he's demonstrated that he can throw strikes, and he's demonstrated that he can miss bats. Within that pool of AL starters, Iwakuma's groundball rate puts him in the upper quarter. He's posted the same contact rate as Dan Haren and David Price, which just caught me completely off guard. He's got as good a strikeout rate as Doug Fister and Jon Lester. Almost wherever you look, Iwakuma's in encouraging company.

Yet, last night was the first time since June 16 that Iwakuma didn't allow a home run. He had put together a streak of ten consecutive appearances with a dinger, and while in all ten of those appearances he allowed just one of them, that's still a lot of dingers. Iwakuma's allowed seven in eight starts, and he's averaged just under 25 batters faced in each. He's a groundballer. When you look at that ol' controversial home run/fly ball statistic, Iwakuma is way up there. Home runs are the reason why Iwakuma's starter FIP disagrees with his starter xFIP. His xFIP is quite good. His FIP is not so much.

The easy thing to do here is dismiss it as noise. We're talking about a guy who has proven his ability to get strikeouts and groundballs, so what sense would it make for him to be homer-prone? As a starter he's allowed just seven homers. This should get more time to balance out.

And it will get more time to balance out, as Iwakuma remains in the rotation. I suspect that he's not actually homer-prone, at least to this degree. I suspect that he's a normal pitcher who will generate normal pitcher statistics, and that it's the other numbers that are more telling. But this is the question Iwakuma still has left to answer. Will home runs be a part of his game, or won't they? That HR/FB stat is tricky because it makes people think that home runs are flukes. A more comfortable way to think of it might be that home runs are often deserved, but over time a guy who's allowed a lot of homers will throw fewer of those dinger-worthy pitches. There's that difference between "luck" and "unsustainability" where the latter is easier to believe in than the former.

So maybe Iwakuma's home runs are unsustainable, and maybe last night was the beginning of that. Or maybe Iwakuma does have a home run problem, and last night he faced a weak Twins lineup in Safeco Field at night. We're going to find out more, and that's going to inform the Mariners' decision of whether or not to try to bring Iwakuma back. The team could probably use a guy like him next season. He's probably not going to get a ton of money, but, maybe he will. Maybe he'll make a fortune. Maybe he'll get injured! It's August, and the season ends in October.

Over just eight starts, Iwakuma's done a real good job in a new old role. We have a good idea of what he is, mostly. We'll see how he holds up, and whether he improves, gets worse, or stays the same. That goes for Iwakuma and literally everyone else. If you're looking for something small to take away from this post, Hisashi Iwakuma has a lower xFIP than Yu Darvish. If that doesn't make you chuckle at least a little bit then I don't know if we have what it takes to be friends. This is the kind of stuff that makes me chuckle. This and squirrels on power lines. How do they do it!