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Process, Outcomes, Patience, and xwOBA

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Are Oakland’s starters actually getting creamed? Or have they been unlucky?

MLB: Houston Astros at Oakland Athletics Neville E. Guard-USA TODAY Sports

One can look at Oakland’s rotation ERA of 4.68, a mark which is in the bottom half of the league, and think it is a staff comprised entirely of batting practice pitchers. A’s starters have allowed 56 earned runs, the 4th-most in baseball and more than 40 more than Tampa Bay Rays starters. My question is are all earned runs really earned? As far as the box score goes, yes. But as far as how they’re earned, my answer is no.

A hitter’s goal is almost always to drive the ball hard either in a gap or over the fence. Even speedy slap would prefer their batted-balls finds gaps between fielders than head directly toward them. Pitchers, on the other hand, desperately want to avoid hard-contact, or any kind of contact for that matter. But when contact is made it would preferably be soft.

Softly hit batted-balls are less effective for producing offense. And Oakland pitchers are among the best in baseball at producing soft contact, or avoiding hard contact.

Oakland starters allow an average exit velocity of just 87.4 MPH to opposing hitters.

AVG Exit Velocity Leaders

Team Exit Velocity xBA xwOBA
Team Exit Velocity xBA xwOBA
LAD 85.5 0.309 0.340
TB 86.3 0.292 0.334
SD 87.1 0.323 0.362
MIN 87.3 0.336 0.392
MIA 87.4 0.315 0.357
PIT 87.4 0.323 0.373
OAK 87.4 0.286 0.329
NYM 87.6 0.355 0.417
DET 87.8 0.319 0.363
WSH 87.9 0.338 0.382

Therefore Oakland pitchers have allowed an expected batting average of .286, the lowest in baseball. And Oakland’s .329 xwOBA is also the lowest.

xBA Leaders

Team xBA xwOBA Exit Velocity
Team xBA xwOBA Exit Velocity
OAK 0.286 0.329 87.4
TB 0.292 0.334 86.3
LAD 0.309 0.34 85.5
HOU 0.312 0.341 88.3
MIA 0.315 0.357 87.4
CIN 0.318 0.357 88.4
DET 0.319 0.363 87.8
BOS 0.321 0.389 88.3
SD 0.323 0.362 87.1
PIT 0.323 0.373 87.4

xwOBA Leaders

Team xwOBA xBA Exit Velocity
Team xwOBA xBA Exit Velocity
OAK 0.329 0.286 87.4
TB 0.334 0.292 86.3
LAD 0.340 0.309 85.5
HOU 0.341 0.312 88.3
MIA 0.357 0.315 87.4
CIN 0.357 0.318 88.4
SD 0.362 0.323 87.1
DET 0.363 0.319 87.8
PIT 0.373 0.323 87.4
ATL 0.374 0.339 88.2

Overall Oakland pitchers have allowed the second-lowest percentage of barrels, narrowly edged out by Houston.

What does all this mean? Not anything as far as outcomes are concerned. Oakland starters have still allowed the 4th-most earned runs in the league. As I stated before, I don’t believe these runs are earned the same way as say, Boston’s 67 as Boston has allowed much harder contact.

This data is a reason for optimism, though. Oakland pitchers are doing what they should and are avoiding well-hit balls. They’ve merely been unlucky. And you’ll never guess who has been the unluckiest.

Oakland Starters: wOBA-xwOBA

Player wOBA-xwOBA BA-xBA
Player wOBA-xwOBA BA-xBA
Marco Estrada 0.040 0.034
Mike Fiers 0.031 0.030
Aaron Brooks -0.020 -0.028
Frankie Montas -0.024 -0.043
Brett Anderson -0.028 -0.030

By comparing his actual wOBA with his xwOBA Marco Estrada has indeed been the unluckiest starter, followed by Mike Fiers. Naturally these two have Oakland’s worst ERAs.

I know what you’re thinking. That these metrics don’t matter. And I’d say again, I know. But only as far as the outcomes go. The process remains intact. Oakland’s starters are pitching to their strengths but not all are getting rewarded for it.

For example, Brett Anderson is middle of the pack in terms of exit velocity. But he also allows the lowest launch angle, resulting in 53.3% ground balls. That is a good recipe for success given Oakland’s elite infield defense. Frankie Montas, however, has been the one of the luckiest pitchers on the staff. He doesn’t allow terribly hard contact, but his 13.9 degree launch angle is much closer to the ideal angle for hitters. Montas’ ground ball rate is even higher than Anderson’s, his BABIP is lowest on the team at an even .200 and he’s stranded more than 90% of runners. All of that is with a below-average strikeout rate.

Oakland Starters: Exit Velocity and Launch Angle

Player AVG Exit Velocity Launch Angle
Player AVG Exit Velocity Launch Angle
Marco Estrada 82.0 32.6
Mike Fiers 85.4 16.3
Aaron Brooks 85.6 14.6
Frankie Montas 82.5 13.9
Brett Anderson 83.7 7.7

I bring this to your attention because it’s far easier to move to throw guys overboard when things go wrong than it is to seek an explanation and solution.

Oakland’s record is just 11-10, but it should be better and by BaseRuns it is. The offense has supplied plenty of runs, and overall the team has outscored its opponents. The data above gives me confidence that better starting pitching is on the horizon. It’s just that it may take the form of better luck, not a major personal change.