September 5, 2012
The Rockies' Rotation, Before and After
In June, you'll recall, the Colorado Rockies announced that they would be going to a four-man rotation, with each pitcher limited to 75 pitches. Josh Outman was the first pitcher to start in the new format, and the consequences of the Rockies’ shift were immediate: lots of people became aware that Josh Outman was pitching for the Rockies now. In the Seth Smith trade? You don’t say!
It’s still too soon to say what the four-man rotation—with 75-pitch limits on the starters—has wrought, and will wrou... uhh... whatever the heck the infinitive of wrought is. Work? It seems to be work. Wrought seems to be the past tense of work. Forget it.
What we do know is that the Rockies say they will continue this experiment into next season, so perhaps truth will emerge. In the meantime, we know this: the Rockies allowed 5.74 runs per game before the switch and 5.32 runs per game since. Done! Fixed! Go away Ervin Santana, teams need only four starters now.
Except that it’s obviously not that convincing. Some regression from 5.74 runs per game was already likely. The Rockies probably wouldn’t have made this move if they weren’t performing at a level far below expectations. They’ve also made plenty of personnel moves, so it’s a comparison between two different groups of pitchers. And 0.4 runs per game isn’t all that much. The Rays and the Mariners, for instance, will likely each have bigger first half/second half splits than that, when it’s all done.
I was curious, though, to see where in the pitching staff the four-man format would bend or break. As Colin Wyers noted back in June, the rotation is just the front of the staff; any innings shirked by starters must be picked up elsewhere. So the Rockies plan could:
a) work, by removing the worst starting pitcher and by keeping starters’ workloads manageable and by keeping starters from getting hit the third time through the order, or