Dallas Keuchel in perspective

What is important for a pitcher? Traditionalists would answer wins. Other, marginally more advanced bipeds would cite the prevention of runs as a crucial task. But the truly erudite among us recognize that there are three things for which a pitcher ought to strive: ground balls, strikeouts, and walks (or rather, the lack thereof). The best pitchers will maximize their outputs of the former two while minimizing their output of the latter; poorer hurlers will lag behind in one or more of these areas.

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Let's shift our focus for a minute. Although the Houston Astros are the worst team in the world for the fourth straight year, they possess a few players who have performed admirably. One of said players is Dallas Keuchel, whose 2.67 xFIP ranks fifth in the majors. He's now the most improved pitcher in baseball, and he's done well enough that we must become cognizant of him. But what's caused his evolution, and from what has he evolved?

In his 2012 debut, Keuchel was objectively terrible. While hitters put the ball on the ground 52.1% of the time against him, they also walked 10.3% of the time while striking out 10.1% of the time. Last year, the walks decreased to 7.6%, while the strikeouts and grounders increased to 18.0% and 55.8%, respectively. This year, though, he's been on another planet: Giving free passes to 5.0% of batters while fanning 22.7% and amassing a 67.7% (!) ground-ball rate, Keuchel and his all-encompassing hegemony have taken the league by storm.

There are some underlying causes here, to be sure (in 2013, he phased out the curveball in favor of a whiff-inducing slider) but right now, I'd like to discuss results — specifically, the three aforementioned results. As you might suspect, that 67.7% worm-burner rate leads the majors this year, as well as for every year, ever*. While not historically dominant, the strikeouts and walks are also impressive: The former ranks 29th, and the latter ranks 18th. When viewed collectively, however, these numbers take on a whole new significance.

*Well, since 2002, but, y'know.

As the above footnote mentions, easily available ground ball data goes back to 2002. Henceforth until now, there have been 1,148 qualifying seasons. Using z-scores, we can make their statistics era-neutral, to compensate for the meteoric rise of strikeouts in recent years. Through this lens, Keuchel's GB, K, and BB rates are reduced to simple numbers: 3.08, 0.58, and -0.92, respectively. But while they may be bland, each of these is also notably better than league average. How common is that?

There are a few ways we can look at this; let's begin with the balanced approach. Of those 1,148 starters, 335 have strikeout z-scores of 0.50 or greater, 375 have walk z-scores of -0.50 or lower, and 321 have ground ball z-scores of 0.50 or greater. However, far fewer player have done all three things simultaneously — 22, to be exact:

So this isn't all that uncommon; Keuchel's not even the only pitcher this year to do it, as the King has continued carrying out his royal duties. Nevertheless, this methodology might sell Keuchel short; while his strikeout and walk rates are solid, his ground ball rate has been otherworldly. Although that 67.7% figure isn't actually the best ever (it's sixth), it's still one of only seven that's three standard deviations above average:

For the most part, the other pitchers on that list either didn't punch out batters or handed out bases on balls too frequently. Aside from Keuchel's 2014, only Brandon Webb's 2006 season featured strikeout and walk rates a half of a standard deviation better than average.

Even if we broaden the scope to, say, two standard deviations, there still aren't many pitchers for whom the across-the-board-0.5 platitude applies:

Of these 44, three — Keuchel, Webb, and Halladay's 2003 — had strikeout and walk z-scores of 0.50 or greater. It just seems to be that when a player dominates in one area, he invariably falls back in other areas. This applies to high-strikeout and low-walk pitchers as well:

None of the 2-z K guys had 0.5 Zs in both other areas, and only two 2-z BB seasons had it: Halladay in 2003 and 2010.

Again, universal superiority is hard to maintain, which shouldn't really come as a surprise — after all, if being exceptional wasn't difficult, then it wouldn't be exceptional. This fact only makes Keuchel's achievements thus far all the more superb; if he can sustain this start, and pitch to the level of 2006 Webb or 2003/2010 Halladay, perhaps the Cy Young (which went to those pitchers) will also be awarded to him. It's unlikely, but hey, if you're a 'Stros fan, you've gotta hope, right?

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All data courtesy of FanGraphs, as of Thursday, May 22nd, 2014.

Ryan Romano is a featured contributor for Beyond the Box Score. He also writes about the Orioles on Birds Watcher and on Camden Chat that one time. Follow him on Twitter at @triple_r_ if you enjoy angry tweets about Maryland sports and live tweeting about Veep, Sundays at 10:30/9:30c on HBO. Boldly running for president. Proudly standing for everything.