Count-Adjusted OPS: Mookie Betts is the Best Situational Hitter in Baseball

By: Evan Boyd | October 23, 2018

You’ve likely heard broadcast crews throughout the postseason refer to a batter being in a “hitters’ count,” one that puts more pressure on the pitcher to throw a strike. Or maybe a hitter “falls behind” in the count, giving the opposing pitcher an opportunity to generate a bad swing on a pitch out of the zone.

Seems simple enough, but there are trends involved no matter the count of an at-bat when factoring in STATS advanced metrics and analysis. And ahead of the World Series between the Boston Red Sox and Los Angeles Dodgers, we’ll take a look at how Mookie Betts – the likely AL MVP – stacks up within a new metric from STATS: Count-Adjusted OPS, which rewards batters who are successful in pitcher’s counts, and punishes those who struggle in hitter’s counts.

For reference, below are the average MLB OPS numbers for each individual count in 2018:

MLB OPS Averages by Count

Count During At-Bat0 Balls1 Ball2 Balls3 Balls
0 Strikes.923.918.9961.785
1 Strike.832.874.9151.387
2 Strikes.384.410.477.797

MLB averages indicate that OPS is way down with two strikes, and way up on 3-1, 2-0, and other hitter’s counts. This is no surprise. A batter is more likely to receive a pitch that he can hit in those counts because the pitcher would like to avoid a walk.

On the other hand, the league average on two strikes is quite small, as pitchers are looking to strike the batter out while the hitter is just looking to make contact. If a player is good at two-strike hitting, then their OPS difference from the league average will be much higher than if they were good at hitting on a 2-0 pitch.  

But what happens if a player gets a hit with two strikes? What about if a hitter grounds out on a 2-0 pitch? That brings in Count-Adjusted OPS, which takes a player’s specific OPS for each individual count and divides it by the league-average OPS for those counts. This is adjusted by the number of plate appearances the player had in that specific count, and multiplied by 100. The adjustment is made so that one count does not outweigh others.

The scaling of 100 is implemented for each count to better show how the player does relative to the league average. A completely average count-adjusted OPS would be 100, meaning that their OPS at specific counts are almost the same as the MLB average at that specific count. This is inspired from a general equation that takes the relative average for any split. But in this case, it takes multiple splits – one for each count.

For example, if a player had a 2.000 OPS on 3-0 counts but only reached a 3-0 count 10 times, that will not overshadow his numbers on all other counts. All of the counts divided by the league average are then summed up.

For you math-savvy folks, the formula is below. The variables i and j represent the number of balls and strikes in the count (i is for strikes and j is for balls).

Betts was a tremendous two-strike hitter this season, as his .925 OPS with two strikes was the best in MLB.

Mookie Betts OPS in Specific Counts

Count During At-Bat0 Balls1 Ball2 Balls3 Balls
0 Strikes1.009.8281.6671.000*
1 Strike1.2621.2571.0001.412
2 Strikes1.019.609.9071.126

*Betts did not have an official at-bat on 3-0 counts, so his OPS on 3-0 pitches is the same as his on-base percentage.

Here are the number of plate appearances Betts had in each count:

Mookie Betts Plate Appearances - Specific Counts

Count During PA01 Ball2 Balls3 Balls
0 Strikes31402415
1 Strike42613851
2 Strikes346995114

Using the formula above, we can calculate his count-adjusted OPS at each pitch:

Mookie Betts Count-Adjusted OPS - Specific Pitch

Count During At-Bat0 Balls1 Ball2 Balls3 Balls
0 Strikes5.525.886.541.37
1 Strike10.3814.286.768.46
2 Strikes14.6916.6929.4126.23

The largest discrepancies for Betts came on 2-2 and 3-2. Betts was able to work deep into many counts this season, forcing the pitcher to throw strikes or make mistakes. He also had more plate appearances in these counts than any other. Not only is the discrepancy between his OPS and the league average large, but he had more than 200 plate appearances in those two situations combined.

Adding it all up, and Betts’ Count-Adjusted OPS is 146.2. That means that Betts was about 46 percent better than the league average at hitting the ball based on the count he is facing this season.

And no one else came particularly close:

Boston had two of the top three players in this category, and three in the top ten. Mike Trout is only fifth on the list, but it might be due to the fact that he was pitched around so many times. Trout reached a 3-2 count in 132 plate appearances, posting a 1.083 OPS. In addition, his OPS with two strikes has actually gone down: he had a .784 OPS with two strikes in 2016 and a .802 OPS in 2017, but it went down to .732 this season.

Although Jesús Aguilar worked the count well in the regular season, he actually was not as good in the postseason. He reached a 3-2 count in the postseason nine times, but struck out four of those times and reached base only three times. This included Game 7 of the NLCS, where he went to a 3-2 count twice, but struck out both times. He also did not make contact on any 2-0 counts and attacked on a 3-1 count just twice (he singled on one).

And for all of you wondering, here were the lowest numbers this season:

Chris Davis made contact on a 2-0 count only SIX times in 522 plate appearances. In addition, he slashed .091/.172/.152 (.324 OPS) with two strikes.

Since pitch counts were tracked in 1988, the highest count-adjusted OPS in a single season was (no surprise) Barry Bonds in 2001, posting a 159.1 count-adjusted OPS. This was the year where Bonds hit a record 73 home runs, posting a .515 OBP and an all-time best .863 slugging percentage.

Not all counts are the same. If a player is a tremendous two-strike hitter, he can be a huge difference versus someone who is not.