Brandon Moss: Plate Discipline and Outcomes

There is exactly one thing which we can say for sure about Brandon Moss: He has power. Lots of it. For proof, see the moonshot he hit against the Rangers on Monday, which ranks as the 24th longest homer in all of MLB so far this season.

There is another thing which we can say with some degree of certainty: He has holes in his swing. Lots of them.

Moss was a total unknown last year, and many called him a fluke. He is off to a decent start at the plate in 2013, but his batting average and power output are both way down so far. We expected his average to drop from last year's .291, but the loss of power is troubling. Let's take a look at some of the underlying peripherals to get an idea of who Moss really is as a hitter.

Here is the standard intro, written by Cuppingmaster:

While most stats take some time to normalize, research has shown that plate discipline statistics reach some level of significance after only about 50 plate appearances. These data are derived from two sources: Baseball Info Solutions (BIS) classifications or PITCHf/x. BIS is basically guys sitting down watching baseball games and classifying pitches. PITCHf/x is MLB's in-house pitch classification that relies on a neural network to decide what pitches are what. Essentially, a really fancy and expensive computer program designed for decision-making. After all this, there are 9 pretty useful statistics:

O-Swing%: The percentage of pitches a batter swings at outside the strike zone.
Z-Swing%: The percentage of pitches a batter swings at inside the strike zone.
Swing%: The overall percentage of pitches a batter swings at.
O-Contact%: The percentage of pitches a batter makes contact with outside the strike zone when swinging the bat.
Z-Contact%: The percentage of pitches a batter makes contact with inside the strike zone when swinging the bat.
Contact%: The overall percentage of pitches a batter makes contact with when swinging the bat.
Zone%: The overall percentage of pitches a batter sees inside the strike zone.
F-Strike% - The percentage of first pitch strikes (BIS only)
SwStr%: The percentage of total pitches a batter swings and misses on (BIS only)

Since I much prefer PITCH/fx classifications, but BIS has two data points that PITCH/fx doesn't use, I've merged the data into one table that describes it all. The first seven columns use data from PITCH/fx, but F-Strike% and SwStr% come from BIS data. All data itself (and the above glossary terms) are from Fangraphs.

We'll begin with the numbers, looking at both 2012 and 2013 (2013 stats and league averages are through May 15):

All stats are from Fangraphs

Also note that Moss's batted ball tendencies are almost exactly the same as last year, with a slight uptick in line drives: 23.5% line drives, 32.1% ground balls, and 44.4% fly balls.

Moss's approach hasn't changed much. He's swinging slightly less, and it appears that this is because he is chasing fewer pitches out of the zone. Considering that chasing pitches was a bit of a problem for him last year, this is a very crucial improvement for him. Better yet, it's not coming at the expense of his swings in the strike zone. It appears that he has successfully become more selective this year. He's also making slightly more contact on his swings as he did last year, but still far below league-average.

As a result of this increased patience, opponents are throwing him more pitches in the zone and more first-pitch strikes. I would expect that he will capitalize on these extra opportunities as the season wears on. He still swings and misses way too much, but at least he's whiffing slightly less than last year; unfortunately, that improvement is not showing up in his strikeout rate, which has increased from 30.4% of his plate appearances to 31.3%. He still strikes out way, way too much.

Ah, but there is good news! His selectivity isn't helping his massive strikeout rate, but it is helping him walk more, to the tune of 12.2% of his plate appearances (up from 8.8%).

Now we know what happens when Moss doesn't put the ball in play. He still strikes out a ton, but he walks about 38% more often. What about when he does make contact?

Last year, Moss's isolated power was .306; this year, it is .181. That's an enormous drop, although everyone should have expected him to fall from his ridiculous 2012 output. It's tempting to say that he's getting robbed of a lot of extra-base hits, as he was by Nelson Cruz in yesterday's game, but his BABIP is every bit as high as it was last year (.359 in 2012, .347 this year). Bad luck doesn't seem to be his problem. So what is?

Moss HR per flyball, 2012: 25.9%
Moss HR per flyball, 2013: 16.7%
2013 MLB average: 11.1%

Last year, a full quarter of Moss's fly balls went over the wall. That put him 4th in MLB for players with 200+ plate appearances, behind only Adam Dunn, Giancarlo Stanton, and Ryan Howard. Regression should have been expected. His 2013 percentage places him 45th in MLB, in between underwhelming names like Alejandro de Aza and Evan Gattis. He's hitting the same number of fly balls, but far fewer of them are clearing the fence.

It really comes down to this question: Do you think that more of Moss's fly balls will turn into homers as the weather warms up? If they do, then his .250ish average and solid OBP will look just fine next to a .475-.500 SLG% and a .200+ isolated power. If they don't, then Moss might settle in as an above-average, but non-star, power hitter. His current wRC+ of 119, and OPS+ of 117, are just fine, but they are a far cry from the 160 figure that he posted in both categories last year.

Given that Moss has become more selective at the plate and learned to lay off of more pitches out of the strike zone, I am optimistic that he will continue to be a good hitter. Pitchers will be forced to challenge him more because they can't get away with feeding him slop out of the strike zone, and he will punish a decent number of mistake pitches. Regardless of whether his power output remains this low or settles somewhere in the middle of his 2012 and 2013 extremes, his increased walk rate should help soften the blow of any loss of production.