One of the most common refrains of the postseason is that good pitching beats good hitting. This is a safe thing to say in a game where the very best hitters in history fail to reach base safely in more than half of their plate appearances. In the playoffs they fail even more often as pitching rotations and bullpens are shortened and front line guys ridden harder. Though it might be that the difference between regular and post season play is diminishing over time.
The gap in offensive production for playoff teams can be seen in the following graph:
If you isolate the regular season performance of only the teams that make the playoffs and compare it to their postseason production, you can see the drop off. In all but three seasons from 2000 on the postseason scoring is lower, and if you weight their regular season scoring averages by the number of games played in the postseason it does not change this result.
On average over this time period the difference has been about .75 runs per game less for these teams in the playoffs. I’ve already mentioned one reason why this is not surprising at all. The ability to cut the rotation and bullpen down, due to more off days and an increased sense of urgency, means that the average pitcher quality is higher in the playoffs. Also, the teams in the playoffs are better than average, so their pitching staffs were probably better even before the culling of their weakest components. There are other factors that could be at fault too, such as cooler weather in October or performance under pressure, but I would guess most of it comes down to the pitching.
So there you have it, pitching beats hitting, but is the gap itself shrinking? If you chart the difference rather than the two lines themselves above it looks like this:
You can see that the trend line over this period has a positive slope of .0137, indicating that the gap is shrinking by that amount per year based on the sum of least squared errors for the data given. This could be strictly due to sample issues since the two largest gaps happen to be the first two seasons shown. I had no easy way of collecting data on the prior seasons, but I will work on getting more info going back to see if in fact the gap between the regular season and playoffs is closing.
It would not surprise me if this gap were in fact getting smaller. The way pitchers are used, especially in the regular season, has changed substantially. Bullpens and starters are used a similar amount in aggregate. In 2014 starters threw 28992 innings and bullpens threw 14620, while in 2000 the split was 28756 to 14488, so not much different. The difference is pitching value, as we can see back on the first chart, and as has been discussed a lot over the last decade, the run environment is shifting. Relievers are throwing fewer innings per appearance and seem to be more dominant. Those reliever innings in 2000 were done with only 12361 appearances versus 2014 when there were 14459 reliever games played according to Fangraphs.
Personally, I think that a lot of these changes, along with things like overall increasing velocity, are making pitchers more dominant. What that also means is that the top end pitchers are going to be less dominant relative to the league because the overall average performance is harder to distinguish yourself from. Clayton Kershaw might win the MVP with his sparking 1.77 ERA, but that gives him an ERA+ of 197 and ties him for 39th all time for a season for a starter. That’s really good, but it is well below similar level performance of not long ago due to how good an ERA+ 100 “average pitcher” is right now. That means when you have good teams playing their best pitchers, the ability to avoid some of the lower tier guys might have less affect overall on the difference from the level of pitching the hitters are normally seeing.
Does all this have any affect on team performance, preparation, or our expectations for playoff games? Yes, it surely does. I have already heard references to the wild card games from the respective managers about how hard runs will be to come by, but maybe that should be less the mind set now. That mind set leads to bunting early in games and other shenanigans of small ball, but the closing gap here may indicate that you shouldn’t expect runs to be so hard to come by that you start gambling to get one at any given time and give up the opportunity for multiple runs. The more Sabermetrically inclined have of course been beating that particular drum for a long time though, so don’t count on a lot of the managers listening. Also, from a preparation standpoint it increases the amount of work as you need to know about more relievers and what situations they are used in, which might also start to increase the value of bats that can come off the bench to counter late game relievers.
Good pitching does in fact beat good hitting sometimes, but good pitching might be more plentiful now than what most of us have been used to. Hopefully your team, if they are still alive and kicking, is aware of that fact and will expect games to be a little more like the regular season and plan appropriately for the drama that is October baseball.