Studies and statistics show that left-handed people are more likely to be schizophrenic, alcoholic, dyslexic, have mental disabilities or overall just be delinquent. Yet left-handers have survived throughout history, despite these evolutionary anchors, mainly due to the element of surprise and the simple fact that they are, well, different.

In the society of Major League Baseball these days lefties aren’t just surviving, they are thriving.

It’s no secret that scoring in baseball has tapered down since the beginning of steroid legislation and investigations in 2005 and 2006. The 2010 season, to this point, marks the fourth straight year in which scoring will have dropped. Through half of the season scoring has dipped around 10 percent from 9.72 runs per game in 2006, the first year of any steroid testing, to 8.96. And while many baseball men are pointing to steroid testing and a new crop of dominating young arms like Ubaldo Jiminez, Tim Lincecum and Steven Strasburg (Or Jiminez, Josh Johnson, and Roy Halladay, as a recent Sports Illustrated cover suggested under the headline, “Pitchers Rule”) as the reason for the decline, I think that they may be overlooking a key piece to this puzzle.

What if I suggested to you that scoring is down so far in this season because of the rise of guys like Brett Cecil, Jonathon Niese and C.J. Wilson and a statistical anomaly skewing numbers toward left-handed pitching?

So far this season MLB lineups are batting just .257 against left-handed pitchers, with the American League hitting a pathetic .255 and the National League at .260 against southpaws. That .257 mark would be tied for the lowest mark of the last decade against lefties and is an astounding 17-point drop from the .274 batting average that the league put up against them in 2007. (The American League hit .276 against southpaws that year, making it an unbelievable 21-point drop in the A.L. between 2007 and 2010.) The 10-year league average between 2000 and 2009 against southpaws was .266; meaning that the .257 average this season is well outside the standard deviation and thus a significant statistical variant.

As a baseball bettor, handicapping teams against left-handed pitching has been one of the staples of my baseball-betting repertoire. By mid-May it is usually clear what teams absolutely destroy left-handed pitching while also knowing which teams struggle against southpaws. And then that information is at the crux of several of my most consistent and profitable systems. It was always easy money when some mediocre, soft-tossing lefty was going up against a team like the Red Sox, Angels, Diamondbacks or some other team that had its way with sinistral pitchers.

However, that’s not the case this year. There has been a revolving door of teams in the Top 10 batting against left-handed pitching this year. Over the last five or six years the Yankees, Red Sox, Angels, Phillies, and Twins have routinely been among the league leaders hitting lefties. None of those teams are in the Top 5 against them in 2010 and only two, the Phillies (No. 8) and Red Sox (No. 9), are in the Top 10.

Another example of the volatility of this market is that a month ago the Yankees were the clear No. 1 team in batting against southpaws, hitting nearly .290. Now they are 12th at just .266.

Further, the Angels, who had long been one of the most reliable teams in baseball against southpaws, are ranked No. 15 in the league batting against lefties at .257. This is just one year after leading the Majors with a .286 average against them. The White Sox have dropped even more staggeringly. They were No. 4 in the Majors last year at .282 and are now the second-worst hitting team in the Majors against lefties at .227.

While this drop-off in production against left-handed pitching is precipitous it’s not altogether unprecedented. In 2000, scoring hit kind of a high-watermark with an average of 10.3 runs per game in the Major Leagues. Perhaps not coincidentally, teams hit a blistering .273 against lefties that year. But then in 2002 that average dropped to .257 and scoring dive-bombed down to just 9.2 runs per game, tied for the lowest total of the decade.

So when you consider that two of the three highest scoring seasons at the height of the steroid era (2000, 2007) also featured the two top batting seasons against left-handed pitching, while two of the three lowest scoring seasons of the last 11 years (2002, 2010) have featured two of the lowest batting seasons against left-handed pitching, I think that we can deduce that scoring is correlated directly with how teams are hitting southpaws.

Naturally, that’s not the only reason that scoring is down. However, my point is simply that no one – not a single baseball commentator, writer, analyst, player or front office person – to this point has tried to make this connection. And if we can be out in front of a trend this broad and this far-reaching then that could create a profitable situation for you and I.

The reasons for this drop-off against left-handed pitching are numerous and subtle. There really isn’t something as overt as “steroids” that we can blame for such a severe decline in such a targeted – though common – area of the sport.

It’s not as if there is a run on dominating left-handed pitchers. Cliff Lee, Jon Lester, Johan Santana are still among the best southpaws in the game. But they have been for several years. The same goes with over-the-hill arms like Andy Pettitte and Jamie Moyer, who keep producing against the lefty-challenged lineups of their respective leagues.

Hell, even Bruce Chen – BRUCE CHEN! – has found his way back into the Majors and is winning. He’s 5-2 with a 3.51 ERA. This is a guy who between 2006-2009 posted a mark of 1-13 with a 6.60 ERA. Now he’s given up just seven hits and five runs in his last 18 innings of work, winning two of those three starts as a significant underdog. Bruce Chen.

So if it’s not an increase in pitching talent then the drop has everything to do with the hitting.

Some of the team hitting shifts and splits are pretty simple to explain. Some teams simply have more power from left-handed batters and are therefore better equipped to face right-handed hurlers. Other teams just don’t hit, period, no matter who is on the mound.

Personnel shifts have a big impact in this arena. Here are two names that have completely changed how I handicap and wager on four teams against left-handed pitching: Vladimir Guerrero and Scott Rolen. When Vlad was in the middle of the Angels lineup they were an automatic play against left-handed starters. Last year the Angels were No. 1 in the Majors against southpaws. His new team, Texas, was just No. 19 against lefty starters. Vlad switched teams, and now all of a sudden the Rangers are No. 4 in the Majors and the Halos are No. No. 15. Not a coincidence.

Rolen has had a similar impact. In 2007 with Rolen and Troy Glaus – another southpaw slammer – in the middle of the order the Blue Jays destroyed left-handed pitching, posting a .296 average for the season. Both players were injured and then were shipped off to other teams. Now Toronto has spent the first half of the season hitting below .200 – as a team – against sinistrals. Presently they are batting .204 against lefties.

In the meantime, Rolen is hitting .313 against left-handed starters in the middle of the Reds lineup. Cincinnati was mediocre at .260 against lefties last season (No. 17). Now they are No. 7 in the league and a respectable 13-8 in their last 21 games against a lefty starter. Granted, that’s not all Rolen. Orlando Cabrera and noted lefty-masher Jonny Gomes have been added, so all of a sudden this group is lethal against lefties. But Rolen is the key and is an example of how fickle these numbers can be from year-to-year.

There is always going to be that type of ebb and flow to teams and how they handle hitting left-handed pitching based on personnel. But, again, this has become a league-wide epidemic. There were some lineups that used to be stacked against lefties that are no more. That has helped to harm the “bottom line” of hitters against lefties. But, again, there isn’t really one main reason that I can pinpoint this year as to why the lefties have been having their way with Major League lineups. Like so much of the mystical mathematics that the game of baseball gives us, it really just kind of is what it is.

But perhaps the “why” is not important. Or at least not as important as what any of this means to our betting style or approach.

From a baseball-betting standpoint, there are two angles to look at. The first is that there aren’t nearly as many teams that are automatic plays against left-handed pitching this year. Detroit and Texas are coming close and Tampa Bay is a stellar 21-9 against southpaws. And when the Mets play at home they are about as good as it gets in the National League against lefties. San Diego is also solid at 17-9. However, none of those clubs is as solid as the top teams in the past have been. So blind betting on lefty pulverizers is an important angle that has pretty much been eliminated from our arsenal this year, at least momentarily.

In regards to fading teams against lefties, the Orioles are just pathetic at 7-21. But they don’t hit anyone, so that’s not a surprise. Seattle is almost as bad, at 9-17 against a lefty starter, with Toronto (7-14) and Arizona (5-13) also good “fade” teams.

The second angle is how we should approach totals in games involving left-handed starters. And the play is simple: bet ‘under’.

Heading into play on Wednesday, July 7, my unofficial count had left-handed pitchers at 286-370 against the total so far this year. That discounts all ‘pushes’ and represents a 56.4-percent clip on the ‘under’ in any game with a lefty starter. Obviously there isn’t a bettor alive that has been playing that angle from the first game of the season. But if they had they would be up $5,540 if they had bet $100 on the ‘under’ in each game with a lefty starter.

There are 38 left-handed starters that have made at least 10 starts so far this season. A whopping 26 of them have a losing record against the total (meaning profit for anyone that bets ‘under’ on each one of their starts), four of them have an outright losing record against the total, and then there are eight lefties that have gone ‘under’ the same amount that they have gone ‘over’. (Obviously the last group would be a losing proposition by blindly betting the ‘under’ to this point, but their results are hardly conclusive.)

Collectively, those 38 lefties with 10 or more starts have gone 233-321 against the total, good for a 58.0 percent ‘under’ rate.

So the lefties are having their moment this year. We may not be able to understand it or explain it, but there is no doubt that whatever forces are at work here are creating one of the major reasons why scoring is down throughout the league. I’m not certain how long this will last, but what I do know is that there are several team-specific situations (fade the Blue Jays, play on the Tigers, etc.) that have presented themselves as well as the more general, basic trend of betting the ‘under’ whenever there is a left-handed starter. Be sure to monitor how this all shakes out in baseball’s second half because I believe that it could be an important factor in making some money through the dog days of the Major League season.

Carpe diem, and good luck.

Robert Ferringo is a professional sports handicapper and one of the nation’s top baseball handicappers. He has turned a profit in three straight MLB seasons and has shown a profit in 10 of the last 14 months that he has been handicapping the sport. Check out his Insider’s Page Here.