Seven of the eight regular position players saw their O-Swing% increase by over 4%, and Brett Gardner, who made an obvious attempt to draw more walks, increased his by exactly 1%. This obviously isn’t good as more swings at pitches out of the zone leads to softer contact, if any at all, and more outs. It’s also troubling for the older players because it could be a sign of decline—as players age and lose bat speed, they start their swings earlier to catch up to hard fastballs, making it more difficult to stay back on breaking balls and pitches out of the zone. Aging doesn’t seem to tell the whole story, however, as this seems to be a team-wide problem, which indicates that the hitting philosophy has changed.
But I’m not sure that’s it, either. Kevin Long has been the hitting coach since 2007, and it seems unlikely that he would switch his philosophy now. If being more aggressive was his philosophy, you would imagine that the Yankees would have seen an increase before this past season, but as you can see, it just happened this past season. Granted, perhaps it has taken this long for the players to buy into his philosophy, but I doubt it. So I decided to look at their overall Swing% (the percentage of times they swing at any pitch; table is below), and there was not a corresponding increase in the number of swings they were taking (if he wants them to be more aggressive, then everyone should swing more). In fact, the only major change is Nick Swisher, but his new approach has been widely examined. We knew he would swing at more pitches, but everyone seems to be swinging at the same rate as always (Gardner is another exception, but his patience has been addressed as well, though he shouldn’t be more patient if the team philosophy is to be more aggressive).
Let’s look at this a different way. Why would you be more aggressive? One, you don’t want to strike out so much, and two, you want your guys to hit. Therefore, we should see a drop in walks (because they’re swinging at pitches out of the zone) and strikeouts (because that’s the whole idea). I looked at the same players’ BB and K rates (table below), and that isn’t happening. Their total team BB rates are essentially the same, and they are actually striking out more often. So either the philosophy isn’t working out, or something else is going on.
After all this, what do we have? The Yankees are swinging at more pitches out of the zone, but they aren’t swinging any more than normal, aren’t walking anymore, and are striking out a bit more. One explanation is that the Yankees hitters have simply lost track of the strike zone. They are expanding their zone and limiting their swings at a similar rate within the zone (to have a similar Swing%, something has to work against the increase in O-Swing%–in this case, Z-Swing% or percentage of times a player swings at a pitch within the strike zone), which is happening as the Z-Swing% decreased 1% from 2009 to 2010 (the percentage decrease is smaller because there are more pitches in the zone). If the reason was a team philosophy or the results of aging, we would expect all swings to go up, but again, that isn’t happening. So, WTF?
Finally, I looked at the plate discipline statistics for every team in 2009 and 2010, and it all finally made sense. You’ll be happy to know that the Yankees have had the best plate discipline (lowest O-Swing%) of any team in baseball for at least two years running, which doesn’t surprise those who lament the 3-hour, 8-minute games (that seems low). You’ll also be happy to know that the entire league’s O-Swing% has increased, which tells me that the Yankees aren’t swinging at different pitches but the pitches are being classified differently. Only 1 team topped 30% in 2009, but 11 teams did in 2010 with 7 other teams with 29+% (no team in 2009 had an O-Swing% between 28.3% and 31.2%). But why didn’t the highest total increase that much, Mark?! The percentage looks the same, but I’d argue otherwise. The Giants were notorious for their lack of patience in 2009, but in 2010, they added Buster Posey and Aubrey Huff, who take their share of walks (Posey, at least, in relation to Bengie Molina). If they had the same team from 2009, it may have been much higher.
What this tells me is that there’s something screwy in the data. I’m not sure what the problem is (or even if there is one. The entire league may have just started swinging at more pitches out of the zone, but that doesn’t really make sense to me. However, they could also have just changed the classification of certain pitches on the borders and didn’t do it for previous seasons), but I’m guessing that wherever the strike zone data is coming from is having issues, which happens while trying to calibrate data from park to park. Listen, all the new stats and technology is great. We know so much more now than we ever have, but we also have to remember that there will still be problems on the margins, where the innovators are still working out the kinks. Hey, at least it’s on the margins.