As a Blue Jays fan I spend a lot of time thinking about luck. The kind of luck that leads to a run scoring on a throw from a catcher hitting a bat that had every right to be in the batters box. The kind of luck that leads to three straight misplays in the 7th inning of an elimination playoff game.
But while LOB and RISP and BABIP are cruel and fickle Fates, the rules of baseball are merciful to pitchers in one respect: the unearned run. The official definition of an unearned run is a run that would not have been scored without the aid of an error or a passed ball committed by the defence. Even kinder is the related provision that clarifies that an error made by a pitcher fielding his position is counted the same as an error made by any other player.
The makers of baseball inherently understood the bones of Voros McCracken’s DIPs theory, and the unearned run is the most basic recognition of the fact that a pitcher can only do so much.
Those were the thoughts in my mind when I made this graph plotting every team’s Def against their unearned runs. The vertical blue line represents the average amount of unearned runs given up per team in 2015.
Intuitively, the teams in the upper-right quadrant who gave up more unearned runs than average despite having plus-defences were unlucky. On the flip side, the teams in the lower-left quadrant who gave up fewer unearned runs than average despite having weak defences were lucky.
It’s weak, but there’s definitely is a correlation between these two stats. The team with the higher Def will commit fewer errors which leads to fewer opportunities for unearned runs to score.
But really all this graph really shows is which teams were good at “buckling down” after committing errors. Even though they graded out as a worse defence than the Royals, the Giants clamped down harder after their mistakes and allowed only 28 unearned runs in 2015, ten fewer than the next lowest team (Marlins) and 48 unearned runs fewer than the highest team (Padres) allowed.
Since unearned runs are based off of errors alone, I pulled that chart out too and found a few interesting things.
The Padres were in the middle of the pack in terms of errors but somehow managed to allow 76 unearned runs to score on just 92 errors. Meanwhile, the White Sox, Athletics, Phillies and Brewers—all teams roughly equivalent to the Padres defensively in 2015—managed to keep most of the runners they allowed on by way of error off the scoreboard.
The Rangers on the other hand allowed just 51 unearned runs on 119 errors. Of course, that doesn’t include postseason unearned runs. The unearned run is merciful, but the Fates are fickle.