Daniel Murphy is always in search of the perfect swing. (Matthew Stockman/Getty Images)

Chris Heisey knows seven percent of ground balls result in extra-base hits because Daniel Murphy told him so. Murphy calls them “seven-percenters.” Heisey never heard of that term before they became teammates last year.

“He’ll just say it randomly,” Heisey said. “A guy will hit a double and he’ll say, ‘That’s a seven-percenter right there.’

It’s a recent entry in the Washington Nationals second baseman’s ever-evolving hitting lexicon. It’s perhaps the most pertinent to his improbable career arc, because the infrequency serves as the philosophical foundation in his abrupt rise from solid everyday player to MVP-caliber face of baseball’s latest hitting revolution.

Murphy emphasizes that the objective in the batter’s box — get a ball in your zone, barrel it, and produce a line drive — remains the same. Yet he sprung to stardom after his 30th birthday absorbing the analytical rhetoric that most front offices have embraced, but clubhouses have shunned, with one recently developed guiding principle: always avoid hitting a groundball.

It’s the latest turn in his lifelong pursuit of the perfect swing, and he’s willing to tell you about it if you’re willing to listen.

“I’ve always enjoyed the swing,” said the 32-year-old Murphy, who’s slashing .325/.380/.555 in 48 games this season. “I’ve always enjoyed watching the swing, learning about the swing. And one of the best ways to retain information is to teach it to someone. So each time I’m talking about hitting, I’m reaffirming in my mind the best way I think it is to attack the baseball.”

Murphy doesn’t impose on teammates. He understands everybody is different. Some prefer feel over information. But if a teammate wants to talk hitting, he obliges. Last month, for example, he advised Heisey on hand positioning, demonstration included, in the visitors’ clubhouse at SunTrust Park. Last July, when Trea Turner briefly encountered the rookie wall, Murphy told him “to swing straight up.” And the list goes on.

“Daniel always figures out a way to start talking about hitting,” Heisey said. “We can be in chapel or bible studies, in the dugout or the clubhouse. It doesn’t matter. I can’t think of anybody I’ve played with that was as passionate talking about hitting as he is.”

Daniel Murphy, midway through his swing. (Jonathan Newton/The Washington Post)

The obsession with finding the perfect swing can be traced to the hours Murphy spent with his little brother, Jonathan, and their father, Tom, at the park down the road from their childhood home in Jacksonville. They’d start in the batting cage before Tom suggested they take ground balls. Jonathan was excited for the switch. Daniel was less than enthusiastic. He preferred honing the pure swing that years later urged Terry Alexander to overlook his defensive shortcomings and recruit him to play at Jacksonville University — the only Division I program to pursue Murphy.

“He’s able to find joy in the tiny little things of hitting,” said Jonathan Murphy, who also played at Jacksonville and then in the Minnesota Twins’ organization from 2012 to 2014. “I think that’s what’s always driven him.”

Alexander called the older Murphy brother “a little obsessive.” He was always in a batting cage, always absorbing everything he could about the craft. The difference is Murphy’s idea of the perfect swing was very different back then. To him, the perfect swing produced a line drive over the shortstop’s head. If he hit it hard, then it was double. Most were singles. That philosophy produced a .398 batting average and the Atlantic Sun Conference player of the year award as a junior in 2006, but little of the power Alexander was certain Murphy possessed.

“We tried to change him when he was in college,” Alexander said. “We wanted him to get more weight back. But do you take the best player in the conference and change him? He hit it the other way and it worked. We decided that the best thing for him was to let whoever drafted him make those changes.”

Daniel Murphy, following through. (Jonathan Newton/The Washington Post)

That team, the New York Mets, eventually did change him, but not for nine years after they selected him in the 13th round of the 2006 draft. Murphy was already a steady everyday second baseman in 2015, even making the NL all-star team the year before, when Mets hitting coach Kevin Long initiated the first phase in his swing transformation: convincing Murphy to get his leg down quicker. The adjustment, Long told Murphy, would allow him to attack the ball instead of reacting to it. Murphy second-guessed the change when he was batting .198 at the end of April.

“He was terrible,” Jonathan Murphy said. “He was like, ‘Should I just ditch this?’ It was his free agent year, which is obviously a big deal. But he stayed the course.”

The next step in the makeover came in August, when Long and assistant hitting coach Pat Roessler presented Murphy some numbers with a simple message: when you pull the ball in the air, you’re dangerous. When you don’t, you’re not as dangerous.

“They had built up the trust with me so I trusted them,” Murphy said. “It had been a culmination of all the work we were doing and so we just went. I was fortunate to have a little bit of success with it early and allowing me to buy in.”

Three months later, Murphy led the Mets to the World Series with seven home runs in their first nine playoff games, including homers in six straight games. Two months after that, he fell into the Nationals’ laps. Last October, he finished second in the NL MVP voting after setting career highs in batting average, on-base percentage, slugging percentage, home runs, doubles, and RBI, proving the postseason outburst was no fluke.

“Basically, Daniel is really unique,” said Jonathan Murphy, now a high school coach. “His hands and eyes are really special. Not to brag about my brother, it’s just a gift that he has. He can put the ball in play with some of the best hitters in the world. It came down to how do you leverage that skill?”

Nationals catcher Matt Wieters met Murphy when they played on different teams in the Hawaiian winter league a decade ago. They discussed hitting, and Wieters noticed Murphy took it to another level.

“He constantly talked about it,” Wieters said. “He’s different than any other hitter I’ve been around as far as how he deep he goes. It’s rare. But it’s what makes him who he is.”

Parts of their conversations have changed as major league teammates in 2017. They now include launch angle and exit velocity and seven-percenters. Murphy now wants to drive the baseball, not just hit it the other way. He reads FanGraphs and studies charts on Baseball Savant. He can tell you hitting the ball at 10 degrees is high enough to get it over the infield and 25 to 27 degrees is the sweet spot for home runs.

“It’s all information and what you do with it,” Murphy said. “You’re sifting through what works for you and what may not be as beneficial to your game.”

Every winter, Murphy takes that information and shares his insights with 40 of the Jacksonville area’s top high school players at a two-night camp he hosts with his brother. It’s another opportunity to talk hitting and approach, launch angles and seven percenters, in his never-ending pursuit of the perfect swing.

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