Having watched Monday night’s wacky back-and-forth Yanks-Red Sox game, I couldn’t help but notice not only the fact that David Ortiz homered, but that he did so with nobody on base and the score 6-1. In fact, all but one of Ortiz’s seven homers this year have come with the bases empty, and six of them have come in low-leverage situations, those where based upon the inning, baserunner, out and relative score simply aren’t likely to wind up very consequential to the outcome of a game. I also noticed that he wasn’t walking much. So I wrote up a quick One-Hopper for Baseball Prospectus:

…Ortiz is still hitting just .235/.301/.500, numbers that come out to a very humdrum .262 True Average, just two points above the league average, and well below what one would expect from a DH. Ortiz’s May numbers (.348/.380/.761) certainly reflect better production, but his ugly 17/3 strikeout-to-walk ratio in those 50 plate appearances is particularly telling. Even amid this month’s spree, he’s not drawing walks, a reflection of the fact that pitchers are no longer afraid to challenge him.

Ortiz’s strikeout-to-walk ratio for the entire year is an abysmal 38/10, and he doesn’t have a single intentional walk to his name — numbers way out of line with his time in Boston. Expressing his strikeout, unintentional and intentional walk numbers as percentages of his total plate appearances, and including his True Averages for reference:

Year    K%     UIBB%  IBB%   K/UIBB   TAv
2003   16.3%    9.8%   1.6%   1.43   .304
2004   19.9%   10.0%   1.2%   1.77   .308
2005   17.4%   13.0%   1.3%   1.22   .324
2006   17.1%   14.0%   3.4%   0.98   .325
2007   15.4%   14.8%   1.8%   0.93   .341
2008   15.1%   11.8%   2.4%   1.06   .292
2009   21.4%   11.0%   0.8%   1.81   .266
2010   34.9%    9.2%   0.0%   3.80   .262
03-09  18.0%   12.1%   1.7%   1.49   .311

One of those lines is not like the others… Still, it’s fair to point out that Ortiz has just 113 plate appearances thus far this year, and that he did rebound substantially last year after failing to homer through his first 164 PA. But it’s also worth noting that through his first 113 PA in 2009, he was only striking out at a 20.4 percent clip and drawing walks at a 10.6 percent clip, for a 1.92 K/UIBB ratio — numbers very close to his year-end rates. Furthermore, it’s also worth noting that according to the work of Russell A. Carleton (a.k.a. Pizza Cutter), it only takes 150 plate appearances for strikeout rate to stabilize, and 200 PA for walk rates to do so, whereas OBP and SLG don’t stabilize until the 350 PA mark. By Carleton’s definition, which refers to the intraclass correlations of equivalent sequences of PA, batting average and BABIP don’t stabilize over small enough samples to fit into a typical 650 PA single season.

As for the leverage aspect, Monday night’s homer came at a point when the Yankees had an estimated 94 percent chance of winning the game; sure, the Sox came back to take the lead and nearly win, and they certainly have a reputation for making such comebacks more often than the average team. A quick comparison of Big Papi’s Boston-era numbers in high, medium, and low leverage situations, split into 2003-2008 and 2009-2010 bins:

High     PA   HR    AVG/OBP/SLG
03-08   723   42  .337/.429/.648
09-10   152    5  .238/.316/.446

Med      PA   HR    AVG/OBP/SLG
03-08  1392   81  .289/.387/.580
09-10   282   14  .251/.333/.482

Low      PA   HR    AVG/OBP/SLG
03-08  1616  108  .286/.394/.593
09-10   306   16  .226/.327/.466

Oh, how the mighty have fallen. Pitchers need not have The Fear when they face Ortiz in pressure situations, as they can challenge him with impunity. That doesn’t bode well for the Red Sox or their fans, and even from this side of the rooting aisle, it’s kind of painful to watch.

But also kind of fun, mwah-ha-ha…