In life in general, in baseball in particular, there can be a period of creeping change that goes unnoticed — and then we wake to a new normal.
One such occurrence appears to have happened now in baseball — strikeouts.
The average American League pitcher in 2012 is averaging 7.3 strikeouts per nine innings. That rate, if maintained the rest of the season — and it’s been holding steady for at least a month now — would be 0.4 K/9 higher than the previous high.
Which came last year.
The strikeout rate has been sneaking higher by small increments for years, occasionally receding slightly only to resume its growth. But the pace has accelerated. In 2005 — one of those years when the strikeout rate shrunk a bit — AL hurlers averaged 6.2 K/9; seven seasons later, we’re more than a strikeout a game higher than that.
Strikeout rates are consistently higher in the DH-less National League; the senior circuit first hit 7 K/9 in 2001, and has been over that pace annually since 2008. This year, 7.6 K/9 — which, yes, is the highest on record.
Meanwhile, the walk rates in the two major leagues remain monotonously consistent — in the vicinity of 3.3 walks per nine innings. With few exceptions, walk rates have been between 3.1 and 3/5 since the mound was lowered for the 1969 season.
Strikeouts up. Walks steady. What in the name of Jim Thome is going on here?
I think it’s sabermetrics. Specifically, it’s rooted in the knowledge that strikeouts are not a zero-sum game.
The work of Bill James and others have determined that
- Strikeouts are no worse than other outs for hitters. What is lost to the offense is often more than gained in increased power.
- Strikeouts are a major positive for pitchers. Pitchers with better than league strikeout rates tend to be more successful and have longer careers.