WARNING: This story contains graphic numbers. Lots of 'em.

The last time the New York Mets and Washington Nationals got together back in late May, Washington held a half-game lead in the NL East and ex-Amazin' Daniel Murphy was doing his best Ted Williams impression in the middle of the Nats' lineup. While Washington has padded its cushion in the month since (the Nats are up 4.5 games entering Wednesday's series finale against New York), Murphy's average has taken a hit.

After finishing the month of May at .397 (the third highest end-of-May mark this century), the 31-year-old second baseman now sits at .349. That's good enough to lead the NL but a far cry from where he was four weeks ago. After an absurd April in which he hit .370, and an even more monstrous May that saw him post a .416 average, Murphy's hitting a perfectly human .253 in June. Matter of fact, after going "only" 1-for-3 in Tuesday's win over the Mets, he's no longer leading the majors in hitting for the first time since early May (see: Altuve, Jose).

So what's changed?

The narrative throughout the first couple months of the season was that, thanks to copious consultation with bat whisperer (and Mets hitting coach) Kevin Long last year, Murphy is a different hitter. And he is. He's crouching lower than before to get more line drives and fly balls and fewer grounders. He's crowding the plate, increasing his ability to pull the ball with authority. He's swinging, as he likes to say, "hard as humanly possible" to maximize damage (and because, well, that's 97 percent of the fun of baseball).

Even though he's still doing all those things at the plate, the ridiculous results have disappeared. Here are three big reasons for that:

1. Air Traffic Control: In each of the past three years, Murphy hit the ball on the ground around 43 percent of the time. Although that's not a ton (the league average over that span was 45 percent), it was more than Murphy liked, which is why he's making a concerted effort to get the ball airborne more often. In April and May, he succeeded: His 30 percent ground-ball rate over the first two months of the season was the fourth lowest in the majors. In June, though, he's back up to 44 percent. Part of it has to do with opposing pitchers' keeping the ball down in the zone more against him -- 45 percent of the pitches Murphy has seen this month are in the lower half of the zone, up from 42 percent prior to June. But weary wheels might have a little to do with it, too. After all, there's only so many times you can crouch before the old jelly legs start to set in.

2. Inside Out: Watching Murphy day in and day out over the initial third of the season, one of the most remarkable things was how, despite hovering over the dish more than a new parent hovers over a toddler, he was still able to turn on the inside pitch and yank it to his heart's content. In April and May, he posted a slugging percentage of .694 against pitches on the inner half of the plate, almost 250 points higher than the league average (.453). But since June 1, he's slugging a more mortal .423 on inside offerings. Says one scout: "Pitchers have started to adjust and they're throwing him away more, so he can't just sit on the inside stuff."

3. Murphy's Law: With the exception of Bryce Harper's superhuman hair, the law of averages applies to everything and everyone -- especially folks flirting with .400 come Memorial Day. More than any other factor, it's that layman's luck that's brought Washington's cleanup hitter back to earth. In April and May, on contact that was classified as either soft or medium, Murphy hit .349. That's more than 100 points higher that the league average on such balls this season (.243). In other words, on top of hitting the ball really hard really often, Murphy was luckier than a horseshoe-shaped rabbit's foot wrapped in a giant four-leaf clover when he didn't. Since then, his karma has cleared out, as he's hitting .188 on soft and medium contact in June. That helps explain the blips in his BABIP. While the league's batting average on balls in play historically stays around .300, the hit artist currently known as Murph had a .415 BABIP through May. Since June 1, his BABIP has dipped to .253. He's even been unlucky on his hard contact: After hitting .733 on lasers in April in May (slightly above the league average of .724), he's down to .647 this month.

"Sometimes you hit it hard right at 'em, sometimes you don't and it falls. That's the nature of the beast," said Murphy after a recent game. "I'm just gonna keep focusing on the process."

The good news for Murphy and the Nats? July is only two days away.