We aren’t quite through a quarter of the 2009 season, so any serious analysis of the results so far will fall victim to many statistical pitfalls. There’s just not enough data on each player to draw meaningful conclusions at this point. Still, we can always look at statistics as results, rather than leaning on them for predictive value. With this in mind, let’s take a look at the pre-season decision to flip Johnny Damon and Derek Jeter in the batting order. This was a move we advocated just days before Girardi announced it. How has it worked out through the first 39 games?

Many baseball minds wanted to see Jeter in the leadoff spot heading into this year. A few wanted to see it before this season. Derek Jeter profiles as one heckuva leadoff guy: good average, high on base, low slugging. The main reason I brought up the switch back in March was because of an article which extolled Johnny Damon’s amazing ability to avoid the twin killing. As we saw last year, Derek was prone to it. He hit into 24 double plays, a career high, in 668 plate appearances, his career low other than his injury-shortened 2003 and his rookie campaign in 1996. This averages out to a double play roughly every 28 plate appearances.

Contrast this with Damon, who hit into just six double plays in 2008. Of course, he had the advantage of hitting first, so the opportunity didn’t present itself as often as for Jeter, the second hitter. Still, Damon averaged a double play every 104 plate appearances. That’s rather impressive. It’s even more impressive if you use baseball-reference’s GDP stat, which only charges Damon with 5 GDP. The 6 figure comes from FanGraphs.

Part of the reason Jeter grounds into so many double plays is that he has become more apt in recent years to put the ball on the ground. He’s seen a decreased line drive rate over the past few years, but rather than increasing his fly ball total he’s mainly put those once-line-drives on the ground. Last season 58.3 percent of his balls in play were on the ground. He’s done that even more frequently in 2009, at 61.2 percent. While we can’t say for certain, it would seem that Jeter would be even more prone to the double play this year, as he’s putting the ball on the ground more.

Since Jeter hits leadoff, he faces fewer situations where he can ground into a twin killing. His first at bat is a freebie, and after that he needs the bottom of the order to get on base, and not record two outs before doing so, to have a chance at a DP. If I had the data at hand I’d check Jeter’s specific numbers in double play situations. Unfortunately, all we have at hand are the aggregate numbers. Jeter has hit into just three double plays so far in 176 plate appearances, or once every 58 2/3 plate appearances. So far, he’s at an improvement over last season. This is better than even his last season hitting leadoff, 2005, when he grounded into a double play every 43.6 at plate appearances.

What about Damon? He’s been a leadoff hitter his entire career, so has been in a position to avoid double plays. However, as the aforementioned study notes, Damon has been stellar in double play situations, not just aggregate double play numbers. Again, since we don’t have those, we’ll go with what we do have. In 169 plate appearances this season, Johnny Damon has grounded into one double play. Just one. This is quite remarkable, even for Damon. It also means that the Yankees one-two hitters have grounded into four double plays in a combined 345 plate appearances, or one every 86 1/4 PA. Last season they grounded into one every 43 PA.

Again, because we’re not yet a quarter through the season these figures might not have predictive value. So far, though, we can say that the experiment has worked, at least as far as the double play concern goes. It would likewise be foolish to attribute Damon’s hot start to his move in the batting order, but there’s no denying his impact on the team this year. Jeter is seeing positive effects too, as pitchers are throwing him four pitches per plate appearance this year, as opposed to 3.76 last year. In other words, both Damon and Jeter have adapted well to their roles, at least in the early goings.

The idea to check in on the lineup switch issue came from Craig Calcaterra, a/k/a Shyster (though it was from a post on NBC), on the uselessness of lineup switches. He cites the same articles used in our lineup discussions over the off-season — one from Driveline Mechanics and one from Beyond the Boxscore. The main argument they make is that an optimal lineup, by the numbers, only yields about one run over the course of a season. Yet as we see with the Damon/Jeter switch, it can mean so much more than that. How many twin killings have the Yankees avoided by making the move? We can’t say for sure, but given the data we have at this point, it would seem that they’ve avoided a number of them. And that can make a huge difference in how a season plays out.