This began with an observation: Since 2008 — covering the bulk of the reliable PITCHf/x era — Miguel Cabrera has swung at just under 47% of pitches with the bases empty, and just over 53% of pitches with a runner or runners on. Now, in that span, 130 different players have faced at least 10,000 pitches. Out of all of them, Cabrera has the biggest positive difference in swing rate. As it happens, Derek Jeter has the biggest negative difference in swing rate, but maybe that’s a different article. Cabrera has swung more with men on; and at bats with men on are more important at bats.

I wanted to dig deeper.

The next step was to break things down by year, to see if there might be a developing trend or a steady pattern. As is often the case, I have to express my gratitude for the existence of Baseball Savant. This table suggests one thing:

Year None On Runner(s) On Difference 2008 47% 54% 8% 2009 47% 55% 7% 2010 44% 54% 10% 2011 45% 52% 6% 2012 46% 53% 6% 2013 50% 52% 2%

As shown in the table, Cabrera increased his swing rate with the bases empty in 2013, and he somewhat lowered his swing rate with runners on. He posted the lowest difference of his recent career, and that’s where I just about stopped digging. But part of me wanted to keep plugging away, and, see, Baseball Savant has this tool that allows you to isolate pitches in and out of the PITCHf/x strike zone. Are you in the mood for some more tables?

Let’s look at the same table as above, but this time, let’s only consider pitches inside the PITCHf/x strike zone:

Year None On Runner(s) On Difference 2008 60% 74% 14% 2009 65% 77% 12% 2010 71% 81% 10% 2011 73% 80% 7% 2012 68% 77% 9% 2013 77% 84% 8%

Each year, with runners on, Cabrera has been considerably more aggressive swinging at strikes. Even last year, despite what was suggested by the first table. So why don’t we look at the same table again, only this time, let’s only consider pitches outside of the PITCHf/x strike zone:

Year None On Runner(s) On Difference 2008 38% 42% 3% 2009 36% 41% 5% 2010 30% 40% 10% 2011 31% 38% 7% 2012 34% 39% 5% 2013 35% 35% 1%

In every season, Cabrera has been more aggressive swinging at balls, too, with runners on. So he’s just swung more often in general, which makes some sense, given that swings with runners on can do more damage than swings with nobody on. But now look at last year. Focus exclusively on last year. With runners on, Cabrera increased his swing rate at strikes by 7.6 percentage points. With runners on, he increased his swing rate at balls by 0.7 percentage points. Cabrera was more aggressive, but in a controlled and disciplined way.

Last season, with nobody on, Cabrera’s Z-Swing%/O-Swing% ratio was about 2.2. That’s right around his recent established average. With runners on, however, his ratio was about 2.4. That’s the best we’ve seen out of him, at least since we started having access to this sort of data. Here’s the short, plain-English explanation: In Miguel Cabrera’s most important at bats last year, he improved his selectivity, swinging at more hittable pitches without also swinging at less hittable pitches.

A potential consequence of that? This might be confusing correlation and causation, but last year, with men on, Cabrera slugged .733, with an isolated slugging percentage of .366 and a wRC+ of 222. All of these were career-best marks, by far. With the bases empty, he was also very good, but he was very good in a typical Miguel Cabrera kind of way. He slugged .549, and put up a 163 wRC+. The difference for Cabrera was plate appearances with men on, and that’s where he demonstrated some never-before-seen disciplined aggressiveness.

What sorts of adjustments might Cabrera have made? Let’s leave behind the runner/no-runner splits. Take a look at this chart, from Brooks Baseball. There are 11 boxes in which — during the PITCHf/x era — Cabrera has slugged at least .500. Two years ago, he swung at 66% of pitches in those boxes. Last year, he swung at 72% of pitches in those boxes. That suggests Cabrera has become more aware of his strengths.

We can also take a different approach. Two years ago, Cabrera swung at 58% of pitches over the middle or more inside. He swung at 37% of pitches over or beyond the outer third. Between 2008 and 2012, those rates were 59% and 38%. Last year, Cabrera swung at 64% of pitches over the middle or more inside and 36% of pitches over or beyond the outer third. Cabrera’s specialty is driving pitches more in than out, and if he has a weakness, it’s making solid contact with pitches away and off the plate. He’s been able to swing at more of the good stuff without also swinging at more of the bad stuff. Two years ago, Miguel Cabrera won the Triple Crown. Last year, Cabrera showed signs of improvement.

They say there isn’t a pitch Cabrera can’t destroy, that he has hands-down the best plate coverage in baseball. That’s probably true. But there are certain pitches he tends to destroy more often than others. Last season, Cabrera swung at more of the pitches that, historically, he’s punished. He didn’t simultaneously increase his swing rate at pitches he has more trouble with. He most showed off his improved eye with runners on base, when he could do the most damage. Cabrera was a nightmare for pitchers before last year, and then he took a step forward.

I don’t know how much of this is sustainable, and I don’t know how Cabrera’s going to be pitched in the future. I’m looking forward to seeing what these numbers look like in eight months. But it used to be said that Cabrera had the best eye in baseball. There’s evidence that, last year, it got even better.