Tigers’ J.D. Martinez was a launch-angle trendsetter

Detroit — You remember what Daniel Murphy did in the playoffs for the Mets in 2015 (seven home runs, four in the NLCS). You see what Ryan Zimmerman is doing in Washington now (13 home runs, 36 RBIs, .385 average).

They did that, and are still doing that, in a large part because they bought into a philosophy of hitting that Tigers’ slugger J.D. Martinez adopted before the 2014 season — a philosophy that states, very simply, hit the ball in the air, dummy.

“That’s exactly what we talked about,” Martinez said. “Get the ball in the air, that’s where the money’s at. It’s been proven that a ball in the air is more valuable than a ball on the ground.”

Generations of hitting coaches just choked on their chew, hearing that. For the better part of 100 years, hitters were taught to swing level, hit line drives. There was even a school that taught hitters to have a slight downward angle on impact because it created back spin that helped well-struck balls carry farther.

These days, advanced metrics and analytics show that the combination of raised launch angle (upper-cut) and exit velocity result in more home runs and extra base hits, which result in hitters getting paid bigger salaries.

“People ask why are there so many home runs in the game today,” Martinez said. “What do you want me to say, the ball is juiced? It’s that a lot of guys’ philosophy of hitting has changed.”

Martinez made his swing change after a disappointing 2013 season in Houston. That year, 34 percent of the balls he put in play were fly balls and 9.5 percent of those were home runs, according to FanGraphs. He was still striving for a level swing path.

That offseason he overhauled his entire swing and his approach to hitting. Ground balls became worthless to him. He wanted to drive the ball and get it elevated. He didn’t have the swing perfected by the time the Astros broke training camp and they designated him for assignment.

The Tigers quickly signed him and the swing changes started to pay dividends.

In 2014, his fly-ball percentage was 37 and 19.5 percent of those left the yard — 22 home runs.

In 2015, his fly ball percentage was 43 and 20.8 percent of those went out — 38 homers.

Last season, missing seven weeks with a broken elbow, his fly ball percentage was 36 and 18 percent left the yard — 22 home runs.

Tigers manager Brad Ausmus has a progressive viewpoint on hitting and he embraces the theory of elevated launch angle and exit velocity. To a point.

“Different things work for different guys,” he said. “J.D. can hit fly balls because he has the ability to hit balls over the wall in any direction. Most guys don’t have that. So it’s a balance. If you are a guy who doesn’t have power in all directions, fly balls turn into outs — especially in this ballpark.”

Andrew Romine is a curious case study on this issue. He does not have power to hit the ball out of the park in all directions, but this offseason modeled his swing change largely on Martinez's. He developed more of an extended, fly-ball swing.

The results thus far have been somewhat mixed. He has hit with more power — six doubles, a triple and two home runs. His .391 slugging percentage would be a career-high for a full season. Yet, his batting average is .230.

“For a hitter who is not as power-laden as J.D. or Miggy (Cabrera) or even Ian Kinsler, hitting fly balls isn’t going to do a lot,” Ausmus said.

Martinez said every hitter needs to develop his own philosophy of hitting.

“But it’s been proven — fly balls are more valuable than ground balls,” he said. “And guys are aware of it. There are studies out there. I read an article on Zimmerman and Murphy and they said it perfectly: ‘The answers to the test are out there, but we’re not following it.’

“It’s stupid not to.”

Twitter @cmccosky