Curtis Granderson, right, of the New York Yankees is congratulated by teammate Mark Teixeira after hitting a two-run homerun in the bottom of the sixth inning against the New York Mets earlier this month. (Mike Stobe/GETTY IMAGES)

When you are bequeathed the swath of earth once governed by Mickey Mantle, Joe DiMaggio and Bernie Williams, it is best that you don’t hit in the .230s. It is best that you don’t collect more strikeouts than base hits. It is best that you, if you are a left-handed hitter, occasionally do some damage against a left-handed pitcher. It is best that, every once in a while, you wind up with a shaving-cream pie in your face.

By the summer of 2010, Curtis Granderson had come to understand that vividly. He was getting booed occasionally at Yankee Stadium. The ruthless New York media were starting to ask whether he was a bust. Manager Joe Girardi was starting to bench him against particularly tough lefties.

So Granderson, who had been acquired in a trade from Detroit in December 2009, decided to do something about it. Beginning in August, Granderson, with the help of Yankees hitting coach Kevin Long, undertook a drastic retooling of his swing — almost unheard of for a player in the middle of a season — that within days had begun to pay off. Beginning on Aug. 14, Granderson hit 14 homers over the season’s final seven weeks.

And Granderson has hit 16 more this season, second most in the majors. If it weren’t for the presence of Toronto Blue Jays slugger Jose Bautista — who has hit 38 homers, or eight more than Granderson, in that same period — the baseball world would be marveling at Granderson’s remarkable show of power.

As things stand, Granderson is perfectly content not to be the subject of any marveling, appearing uncomfortable with any suggestion that he now warrants the label of “slugger.”

“I just go up there and try to put the ball in play, and hopefully put it in play hard,” he said. “If [a homer] happens, great. If not — I’m not trying to [hit home runs]. I can’t do it. I’ve never been that guy that could.”

In a lineup full of nine-figure contracts and Hall of Fame résumés, it is Granderson who, more times than not, is the one carrying the Yankees’ offense. While Derek Jeter keeps pounding weak grounders into the earth, and Jorge Posada struggles to get above the Mendoza Line, and Alex Rodriguez posts his lowest slugging percentage (.481) in 14 years, and Mark Teixeira puts up the lowest batting average (.258) of his career, Granderson keeps on hitting home runs and posting an OPS (.982) that is some 150 points above his career norm.

“He’s a power hitter,” said Bautista, during a Blue Jays-Yankees series in the Bronx. “He might as well embrace it.”

Oddly, almost all of Granderson’s improvement this season can be accounted for in his at-bats against lefties. For his entire career — which includes a 30-homer season in 2009 and a 23-triple season in 2007 — he has always been able to hit right-handers, posting a career slash line through 2010 (.287/.363/.527 in batting average/on-base/slugging) that is roughly in line with what he is doing this season (.273/.354/.554).

But against lefties, Granderson had always been virtually worthless, going .215/.274/.346 through 2010. This season, however, Granderson has bashed lefties to the tune of .304/.361/.804. Having never before hit more than five homers in a season off lefties, Granderson this year has already done so eight times (through Wednesday).

Long cringed when asked if the pre-2011 label on Granderson — that he simply couldn’t hit lefties — was fair. But then he thought about it for a moment. Numbers don’t lie.

“Yeah, it was fair,” he said. “When you’re hitting .200 or whatever it was against [lefties], six years into your career, it’s pretty much understood that you’re going to do your damage against right-handers, and against lefties you’re going to struggle. Fortunately for us, he’s been able to reinvent himself.”

The reinvention was undertaken with the goal of shortening Granderson’s swing, which tended to get long and overly complicated. It featured a shift in his stance, from an open one to one that is more closed, and to a two-handed follow-through, instead of a one-handed one. According to Long, the swing change was never solely about improvement against lefties.

“You can talk to a guy about hitting lefties all you want — telling him to stay in [his stance] and stay back,” he said, “but if you don’t get your swing right, none of it is going to matter. The key to hitting lefties [for a left-handed hitter] is to stay in there as long as you can, and having a lot of length to your swing would cause a lot of problems.”

It also didn’t hurt that Long throws left-handed and is willing to pitch batting practice to Granderson until his arm falls off. But it is one thing to go deep against Kevin Long in BP, and another to do it against elite southpaws Jon Lester and David Price, as Granderson did in back-to-back games earlier this month.

That was the work of a smooth-swinging, stone-cold lefty-killer. That was the work of a bona fide home run hitter, a slugger. Might as well embrace it.