NEW YORK — Maybe it's the wind, not unusual for April — gusty, and sometimes blowing in strongly from the west.

Or maybe it's the right field wall, a couple of feet lower, and as much as nine feet closer to home plate.

Or it could be the gentle slope of the stands, rising more gradually from the field without the old sharply stacked tiers leading to the upper deck.

Maybe it was just bad pitching. Or the balls. Or if you are the superstitious type, perhaps it's the new incarnation of the fabled "Curse of the Bambino," with the game's greatest legend angry that the House That He Built has been torn down and replaced with a new edifice across the way.

Whatever it is, it ain't normal. After just four games (through Monday), 20 home runs had been hit at New York's new Yankee Stadium. And the vast majority of them, 14, had been hit right there, to right field, routine-looking fly balls that suddenly took off, whether by wind or luck or other-worldly intervention.

Twenty homers in the first four games sets a dubious record for a brand new ballpark. And with this stadium costing a whopping $1.5 billion, making it the most expensive in the country if not the world, many baseball fans and even some team officials are wondering whether a design flaw may have created an unintended hitter's haven for cheap home runs.

The Yankees have always been a team of big hitters, going back to the Bambino himself, Babe Ruth, a powerhouse lefty who aimed for that short right field porch in the old Yankee Stadium.

But last winter, the Yankees spent a reported $243.5 million to beef up their pitching staff — and presumably would not want to see visiting team hitters salivating at the thought of a veritable wind tunnel over that expensive right field wall.

Other teams now adjusting to new stadiums during this April do not have similar issues. Across town in Queens, the Mets, playing at the new Citi Field, are finding the opposite problem — home runs are tougher to hit than at the old Shea Stadium, with a stingy total of 10 in the first six games. And Nationals Park in Washington, in its second season, featured 18 homers in the first six games — more because of the Nationals' pitching than the wind or sloping stands.

At this early date, in the first month of a long season, the new Yankee Stadium now tops the list of home run venues, with an average of five per game. By contrast, at Camden Yards in Baltimore, home to the Orioles and long known as a hitter's park, teams managed only 17 homers in the first six games.

There is no shortage of theories to explain this string of right field homers at Yankee Stadium, so let's start with the first: the weather.

Last Friday and Saturday, when most of those homers were hit, the winds were from the west, at between 12 and 25 mph, according to AccuWeather.com. Meteorologists said it is possible that the shell of the new stadium could cause high winds to blow across the field uninterrupted, unlike the old Yankee Stadium, where the stacking of the seats produced more of a swirl effect.

The bad news for the Yankees, and for those baseball connoisseurs who prefer pitching duels to home run derbies, is that "as we get later into the season, west and southwest winds will be much more common," AccuWeather senior meteorologist Tom Kines said. "This is something we're going to have to wait a few months to see."

And then there's the little matter of that right field wall.

The new $1.5 billion stadium is supposed to be a near-replica of the stoic old one just across the street, but with more modern amenities like more toilets, slightly bigger seats, and added luxury boxes. But the differences, though minor on the grand scale, could be crucial. Greg Rybarczyk, the creator of Hit Tracker, which tracks every home run in Major League Baseball, used satellite imagery and photographs of the old stadium, and engineering plans for the new park, and determined that right field is indeed shallower in the new stadium.

Rybarczyk also found that the right field fence in the old stadium was about two feet higher than the current one — which could mean the difference between a fly ball and a homer in some cases.

Rybarczyk is also investigating the intriguing possibility that this season's balls could be "livelier" than last year's. "Manufacturing processes tend to shift and drift over time," he said, "And it's entirely plausible that this year's batch of baseballs is within specification, but just slightly more resilient than the prior year's batch."

Add a shallower right field to a lower fence to a bowl shape that funnels a strong westerly wind — and the result could be a record number of home runs hit out of the park.

"You get enough little things together and, boom, there you are," said David Vincent, a home run researcher for the Society for American Baseball Research and the author of the book "Home Runs Most Wanted." Vincent said four games is too early to pronounce a trend, and he believes bad pitching in those early games may have been as much of a factor as weather and sloping stands. "We'll see what happens," he said.

Of course, it could also be a curse.

At the opening of the new stadium, Yankee officials laid one of Babe Ruth's bats at home plate before the game. Vincent remembers thinking, "I bet Ruth's really (angry) at them for moving out of The House That Ruth Built."

"It's the curse of the Bambino," said Vincent. "It's just funny now that the curse is on the Yankees instead of the Red Sox."