THE BOOK--Playing The Percentages In Baseball

Sunday, October 09, 2011

How do starters perform by inning?

First thing I did was look at elite relievers.  I defined an elite reliever as the top 20 relievers or so according to my projections going into year X.  Then in year X, I looked at how they did in the 7th, 8th, and 9th innings (in all games), and what the batter pool was in each of those innings (based on those batters’ overall stats for that year), as well as the platoon situation for that batter pool in each of those innings buckets.

Here is the data:

Elite relievers

6th inning or earlier

Performance in 6th or earlier, .291 wOBA against.
Batters in this bucket were .336 batters overall.
53% batted from the same side as the pitcher.
The pitchers in this bucket were .307 pitchers (wOBA against) for the year.

7th inning

Performance in 7th, .315 wOBA against.
Batters in this bucket were .338 batters overall.
56% batted from the same side as the pitcher.
The pitchers in this bucket were .289 pitchers (wOBA against) for the year.

8th inning

Performance in 8th, .287 wOBA against.
Batters in this bucket were .339 batters overall.
51% batted from the same side as the pitcher.
The pitchers in this bucket were .289 pitchers (wOBA against) for the year.

9th inning

Performance in 9th, .289 wOBA against.
Batters in this bucket were .338 batters overall.
47% batted from the same side as the pitcher.
The pitchers in this bucket were .283 pitchers (wOBA against) for the year.

It looks like against elite relievers (presumably the first and only time through the order - because they are generally short relievers, although I did not track times through the order), we expect a normal pool of batters in the 8th and 9th innings, with slightly more favorable platoon situations for the batting team (presumably because of pinch hitters), hitting around .288 in wOBA, which is somewhere in the neighborhood of these relievers’ overall seasonal stats.

Here is the list of the (elite) relievers going into 2010:

Mike Adams
Betancourt
Broxton
F. Cordero
Devine
Francisco
Hoffman
Kuo
Nathan
Papelbon
Rhodes
Rivera
K-Rod
Saito
Soria
Soriano
Street
Thornton
Valverde
Wagner
B. Wilson

Now what about elite starters pitching in the 9th, presumably while facing the lineup for the 3rd or 4th time?  I used the top 10 or so starting pitchers for each year, 07-10, according to my projections.

First we’ll just look at innings, like I did above with the relievers:

6th inning or earlier

Performance in 6th or earlier, .313 wOBA against.
Batters in this bucket were .340 batters overall.
39% batted from the same side as the pitcher.
The pitchers in this bucket were .315 pitchers (wOBA against) for the year.

7th inning

Performance in 7th, .293 wOBA against.
Batters in this bucket were .332 batters overall.
39% batted from the same side as the pitcher.
The pitchers in this bucket were .313 pitchers (wOBA against) for the year.

8th inning

Performance in 8th, .305 wOBA against.
Batters in this bucket were .335 batters overall.
37% batted from the same side as the pitcher.
The pitchers in this bucket were .312 pitchers (wOBA against) for the year.

9th inning

Performance in 9th, .267 wOBA against.
Batters in this bucket were .338 batters overall.
41% batted from the same side as the pitcher.
The pitchers in this bucket were .308 pitchers (wOBA against) for the year.

Looks to me like the pool of batters in the 9th inning that a starter faces is roughly an average batter, so there probably is not a bias toward the top or bottom of the order.  The pool of pitchers that pitch in the 9th is obviously better than the overall pool of elite starters by around 7 points in wOBA against.  The starters face slightly more same side batters in the 9th than earlier innings, despite there likely being some pinch hitters in the 9th, suggesting that starters tend to pitch the 9th when there are same side batters coming to the plate, but only slightly so.

Somehow though the performance of these pitchers in the 9th is almost 40 points better than expected (.267) given the overall talent of the pitchers (.308) and the quite typical talent of the batters (.338).  This is despite it being the 3rd or 4th time through the order.

I also looked at average starting game time temp in each bucket as well as the average park factor.  All buckets were around the same, so it is not like our starters who pitches the 9th tended to do so in cold weather and in pitchers parks.  In fact, the average game time temp in bucket 4, the 9th inning, was one degree warmer than in the other buckets for some reason (including indoor games).

So unless I am missing something, it looks to me like there is something special about a starter pitching the 9th, at least an elite starter.  It is looking more and more like their stuff is “on” that day and/or their pitch count is low, or something else that the manager and pitching coach can identify.

That may even be the case in the 8th inning. The starters’ performance in the 8th is around what we would expect based on their overall talent, so we don’t seem to see the 3rd (or 4th) time through the order penalty that we expect.

It may be that the “times through the order” penalty may only be applicable when a pitcher is having a bad game and those 2nd, 3rd and 4th times through the order occur early in a game.

Interesting stuff and it appears that I may have been wrong for a long time about taking out a starter who has pitched well and bringing in a reliever.

I would like to look at all starters or non-elite starters to see if the same or a similar thing occurs.

I would also like to look at 3rd and 4th times through the order in early innings (suggesting a bad game for the pitcher) compared to the late innings (suggesting an average or good game)…