Once upon a time in baseball, a ground ball up the middle was actually a hit. And, amazingly, a line drive to short right field used to land in open space, instead of the glove of a second baseman standing 40 feet behind the infield dirt.

But that, of course, was way, way back in baseball's prehistoric era -- in, like, 2011. Before The Shift began to devour baseball life as we used to know it.

Believe it or not, we've uncovered shocking evidence that this sport hasn't yet reached the stage where some sort of devious shift is in place on every single pitch, to every single hitter. And if you can keep a secret, we can tell you why:

It's because some players are still "shift-proof." Really. No kidding.

Oh, not David Ortiz or Ryan Howard or Adam Dunn. They remain the living embodiment of why shifts were invented in the first place -- to mess with slow, pull-hitting mashers who aren't wired to hit a ground ball through the left side, even when there isn't an infielder within 50 feet of the shortstop hole.

But there are still hitters walking the earth who defy modern shifting. With bat control. With brain power. With the increasingly rare ability to swing at a pitch in nearly any quadrant of the strike zone and hit it where the defense isn't standing.

So who are the most "shift-proof" hitters in baseball? There are more than you might suspect, to be honest. But here are five who belong on anyone's list:

#66 RF

Los Angeles Dodgers

2014 STATS

GM 47

HR10

RBI38

R28

OBP.445

AVG .346

If you think Puig is still a wild, uncontrollable, hacking machine who's up there wailing away, here's our advice: It's time to start watching him more closely.

According to Baseball Info Solutions, he'd been shifted on in only 1.3 percent of his plate appearances through Monday. And that, just as much as his .345* average and .440* on-base percentage, is an indication of how tough he has become to both pitch to and defend.

Over his career, Puig has pulled the ball in 77 percent of his ground balls and short line drives, a fairly high rate for a guy who isn't shifted on much. But when one NL scout who helps devise his team's shift strategies was asked why Puig has gotten so shift-proof in his second year in the big leagues, the scout replied: "You just can't do it anymore."

"The reason is .345* and that high on-base percentage," he said. "He's going line to line now. He's not chasing much. And he's spitting on those sliders off the plate that he used to swing at. Too much strength to all fields to shift on."

#22 CF

New York Yankees

2014 STATS

GM 49

HR2

RBI18

R25

OBP.333

AVG .259

Ellsbury is a guy whose pull percentage might seem high on the surface (67.8 percent of his ground balls and short line drives, to be precise). But that's actually a lower-than-average rate. And that's not all he has going for him.

He has become a tougher and tougher out and a hitter you don't want to invite to slap the ball through any gaping holes. He, too, has been shifted on in only 1.3 percent of his plate appearances this year, according to Baseball Info Solutions.

"He's just a guy who naturally hits the ball where it's pitched," said an AL front-office man who is in on his team's shift discussions. "And he's done a lot better job of that of late. He's just a really coordinated guy with bat control, and he's trying to get on base. He does have power numbers in his past. But from the seventh inning on, especially, you don't want to leave a hole on the left side for him to shoot a ball through."

#7 1B

Minnesota Twins

2014 STATS

GM 44

HR2

RBI15

R25

OBP.364

AVG .283

Who would want to mess with shifting on Mauer, a three-time batting champ with one of the lowest pull rates in baseball (just 30.7 percent of his ground balls and infield line drives, according to Trumedia)?

Oh, some teams have tried it -- but they must wonder why they did. Baseball Info Solutions' data shows that Mauer is hitting .600 this year (6-for-10) on ground balls and short line drives against the shifts he's seen. Yeah, .600.

"He's really hard to shift on," said the AL front-office man quoted above. "Not only does he naturally drive the ball on the ground all over the field, but if you did make an adjustment on how you played him, he has such good, controlled at-bats that if you left half the field open for him, it wouldn't be a fun day."

#7 SS

Toronto Blue Jays

2014 STATS

GM 36

HR3

RBI15

R28

OBP.323

AVG .247

We won't need to stage any impassioned debates over whether Reyes is "shift-proof." He hasn't been shifted on in even one plate appearance this season. Not from the right side. Not from the left side.

His pull percentage is higher when hitting right-handed (77 percent) than it is when he bats left-handed (67 percent). But if you include all plate appearances, you find a hitter who has an incredibly even distribution of balls on the ground, balls in the air and balls sprayed to all sections of the field. No wonder no one bothers shifting.

"He's a guy who's very tough to shift against," said the same AL front-office man. "One, he can bunt very successfully. And two, he's very good at slapping the ball the other way. So guys like him -- who can bunt and have that sort of bat control -- are very hard to shift on."

#4 C

St. Louis Cardinals

2014 STATS

GM 46

HR5

RBI23

R22

OBP.354

AVG .317

There are many ways to measure the ascension of Molina as an offensive force. Here's one more: He, too, is now practically shift-proof.

The only team that has even tried a partial shift on him this year is the Brewers. They tried it in three at-bats. He got two hits. So what's the use?

"You can't do it. He stays inside the ball too much and he guesses so well," said the NL scout quoted earlier. "He knows what you're trying to do to him. So I've seen him get a pitch middle-in and drive it out the other way, or he'll stay inside that ball and shoot it to center field. We're talking about big-time, big-game bat control."

How do you convince those teams you play to save their shifts for somebody else? Big-time, big-game bat control ought to do it. What a concept.

And now 10 more names who are foiling the shifting plans of managers and data-crunchers from coast to coast:

Five more shift-proof left-handed hitters

Five more shift-proof right-handed hitters