In a recent post I discussed my analysis of the why some hitters bring their “A” game into the postseason, while others seem to take it down a notch or two. My analysis does not deal with a player’s makeup or psyche, or how they handle pressure, nor does it have anything whatsoever to do with the topic of clutch performances. I’m coming at this from a different angle, with a data-based look at how hitters perform against different strata of pitching quality. The reason this analysis may have implications for a hitters’ postseason performance is the quality of pitchers in the postseason differs (by a lot) from regular season pitching. My hypothesis is simple—hitters who have a track record against top pitchers will survive or even thrive in the postseason, while those who are systematically beaten down by top pitchers will have a tough time shining in October.

On average, hitters follow a pattern—they perform at their average level versus “average” pitching, better against “weak” pitching, and worse against “top” pitching. Using OPS as a calibration point, hitters hit about 80 to 100 points lower against the top one-third of starting pitchers and about 80 to 100 points higher against the bottom 33%, on average. Not everyone follows the same pattern. Some are particularly effective against top pitchers and hit only marginally better against weak pitching. Others have the opposite profile—they exploit weak pitching, while being stifled by top pitching. Alex Rodriguez profiles in the latter group. Because postseason pitching tends to be comprised of more top tier pitchers, (see my previous post) we can expect players like A-Rod to produce at a lower level during the postseason.

Let’s start by looking at Alex Rodriguez’s regular season hitting versus different quality levels of pitching. I created an index of a player’s OPS relative to the MLB average, against top pitching and weak pitching. If a player indexes above 100 he performs relatively better against top pitching; if he indexes below 100, he performs relatively worse against top pitching. A-Rod indexes at 92, while Derek Jeter indexes at 114. Mark Teixeira, who has also had his postseason struggles indexes at 94, while Robinson Cano comes in at 109. For perspective, one of the highest indexes for any player currently in the postseason is Carlos Beltran, who scores a 121 on this measure. Is it a coincidence that Carlos Beltran crushes high quality pitching—in 115 postseason plate appearances he has a 1.297 OPS? Several other marquee players currently in the postseason are listed below:

Let’s compare Jeter and A-Rod’s actual postseason performance over their career. We can’t simply look at all regular season stats vs. postseason stats, since a player may have reached the postseason in his best or worst hitting seasons. Instead, I weighted the player’s regular season OPS based on the number of plate appearances in each year they reached the playoffs. This gives us more of an apples-to-apples comparison. For his career (prior to this postseason), A-Rod have a blended average .945 OPS for the regular season and an .884 OPS in the postseason—a downgrade of 61 points. Conversely, Jeter’s regular season numbers are .830, with a postseason OPS of .839. Here’s an instance where the actual performance, over a 15-year career, supports the analysis of who succeeds in the playoffs.

Over the course of a postseason a player may have a hot or cold streak, so the small sample size means this framework may not translate in the short run. A-Rod proved that with his 2009 postseason as he carried the Yankees to a World Championship. Nonetheless, the approach of determining whether or not a hitter crushes (or flounders) against top pitching may provide a window into their postseason performances.