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Justin Masterson vs. Rick Porcello

Despite differences in strikeouts, the two pitchers are very similar. Using standard deviations, we can see how their performances align with historical precedent.

Masterson about to fly away.
Masterson about to fly away.

Clearly when one thinks of Justin Masterson and Rick Porcello, one thinks of two different people. However, when one takes into account the nature of their employment and the results of said employment, Masterson and Porcello emerge as similar.

Both gentlemen are big right-handers who generate more ground balls than most other pitchers. Observe their results from the past three seasons:

Justin Masterson 615.33 19.6% 8.8% 0.61 56.1% 3.86 3.60 3.71 9.5
Rick Porcello 535.33 15.3% 5.7% 0.87 53.2% 4.56 3.83 3.70 8.7

Masterson strikes out more hitters, but Porcello is more adept at avoiding free tickets to first base. Both guys are between one and two standard deviations above the middle in ground ball rate. Masterson has also thrown more innings and has a lower ERA, but Porcello has dealt with statuesque defenders at the hot corner and less hot corner. When focusing on the more controllable results, represented in a way by xFIP, these two fellows have been pretty much the same pitcher.

Analyzing the past three years loses some level of granularity; here is the exact same table as above, but with only the previous season's results.

Justin Masterson 193 24.3% 9.5% 0.61 58.0% 3.45 3.35 3.33 3.4
Rick Porcello 177 19.3% 5.7% 0.92 55.3% 4.32 3.53 3.19 3.2

Again, both pitchers, despite being different individuals, reached a similar epiphany regarding strikeout ability. Porcello increased his K% by almost 6 percentage points from 2012, and Masterson increased his K% by a slightly greater seven percentage points from 2012. Perhaps these two chanced an offseason encounter in which they discussed the merits of the K and decided that their games lacked an adequate number of them, but who knows.

The 2013 increase presents an interesting exercise. Both pitchers' walk and ground ball rates stayed relatively stable while the strikeout rate climbed the beanstalk higher into the clouds. Masterson gained an additional 1.5 fWAR from the previous season, while Porcello gained only 0.2 fWAR, which is not really significant. Looking to the past might give us some clarity on how this might have occurred.

Hopefully, you are familiar with my notation system from my standard deviation research. If not, look here. In 2012, Porcello found himself in group (0-1, 0-1, 1). In 2013, with an elevated K%, he found himself in group (0+1, 0-1, 1). Here are the results of each group.

ERA- FIP- xFIP- fWAR Sample Size
(0-1, 0-1, 1) 113 101 98 1.5 43
(0+1, 0-1, 1) 87 88 87 3.3 27

It looks as though the overall package Porcello brought in 2012 was more than the parts, as Porcello appears to have outperformed that group in fWAR. However, Porcello's IP was in the upper echelon of the group, so naturally his fWAR would be higher than the median. In 2013, Porcello's performance lines up quite well with historical precedent.

Meanwhile, Masterson found himself in group (0-1, 1, 1) in 2012, and below is a table comparing that group to group (1, 1, 1), where Masterson was in 2013.

ERA- FIP- xFIP- fWAR Sample Size
(0-1, 1, 1) 120 112.5 111.5 0.6 10
(1, 1, 1) 91 93 85 1.7 5

The increase in Masterson's fWAR seems to be real based on his K% increase and historical precedent. However, in both years, Masterson seems to have outperformed the historical figures in fWAR. This is simply because Masterson possesses a skill that others within his groups do not: durability. Masterson led his groups in IP in both years, but his ERA-, FIP-, and xFIP- match the groups well.

It seems that Porcello and Masterson are both relatively durable ground ball pitchers whose performance aligns generally well with historical precedent. Should Masterson and Porcello retain their increase in K%, they are likely to continue producing at 2013 levels.

. . .

All statistics courtesy of FanGraphs.

Kevin Ruprecht is a contributor for Beyond the Box Score. He also writes at Royal Stats for Everyone. You can follow him on Twitter at @KevinRuprecht.