Take a quick glance and you might not be particularly encouraged by what Clayton Kershaw has done since returning from the disabled list. There's nothing wrong with a 3.32 ERA, but Kershaw hasn't finished with an ERA that high since he was a rookie. You'd be tempted to think Kershaw's under-performance is one of the reasons the Dodgers are looking up at the Giants in the standings. But we can go deeper than this. For one thing, it's worth acknowledging Kershaw's one disastrous start against the Diamondbacks. This is bad analysis, but if you forgive Kershaw for a bad day, his ERA drops from 3.32 to 1.94. He's been outstanding, except for once. And we don't even need to mess around with ERA anyway, since we have more meaningful numbers at our disposal. If you believe what the numbers are saying, Clayton Kershaw might've somehow improved. It all comes out of the following foundation: the very best pitchers get strikeouts, limit walks, and limit homers. In order to limit homers, it's preferable to limit fly balls. There are 114 starting pitchers who have thrown at least 40 innings this year after throwing at least 40 innings last year. Kershaw is among 62 of them who have improved their groundball rates at least one percentage point. Out of those guys, Kershaw is among 25 who have also improved their strikeout rates at least one percentage point. Out of those guys, Kershaw is among nine who have also improved their walk rates at least one percentage point. Out of everybody, Kershaw's walk-rate improvement ranks 21st. His strikeout-rate improvement ranks 12th. His groundball-rate improvement ranks third. Already silly, Kershaw's more advanced numbers have become absurd. What's fueling this? As they say, it all begins with strike one. Kershaw averages a first-pitch strike to three of every four batters, the highest rate in baseball among starters since at least 2002. What happens when you throw first-pitch strikes? You don't throw first-pitch balls. A pitcher's able to get ahead and possibly stay ahead. The league-average rate of pitches thrown with the pitcher behind in the count is 17 percent. A year ago, Kershaw came in at 15 percent, better than average. This year, he's at 11 percent. Kershaw's ahead more than ever. And when the pitcher is ahead, the hitter has to be on the defensive. What else do we observe? Kershaw's throwing seven out of every 10 pitches for strikes, one of the highest rates in recent baseball history. It's not that he's throwing a ton more pitches in the strike zone; it's that, behind, hitters have had to swing at more pitches out of the strike zone. A pitcher who works ahead forces hitters to expand, and what we see is that, last year, hitters swung at 33 percent of Kershaw's pitches out of the zone. This year they're up to 40 percent. Pitchers love swings at balls, regardless of whether the swing makes contact.