More on AL relief appearances
Posted by Andy on January 14, 2010
I feel like we've unearthed some interesting stuff on this topic, so here's another helping.
Here are the fraction of AL relief appearances lasting less than one inning, more than one inning, or exactly one inning.
The red line is one that we've seen before, from the earlier posts where we were looking at relief appearances of exactly one inning. The blue and green lines account for all other relief appearances. Remember (plus for those of you who didn't read the earlier posts) that all of these numbers exclude save opportunity appearances (of less than, more than, or exactly one inning.) You'll notice that for any given year, the values for the three lines add up to 100%.
Interesting things to note about the above chart:
- Appearances of less than 1 inning have never been the majority in MLB (at least since 1954, and I very much doubt before then either.) It got close in 1998, though, when all three possible types were just about even.
- Reader eorns was correct that when appearances of exactly 1 inning dropped off in 1973 due to the arrival of the DH, the slack was picked up by appearances of more than 1 inning, probably due almost entirely to the fact that the relief pitcher didn't come up to bat in the intervening half-inning and therefore was not lifted for a pinch-hitter.
- Since that spike in 1973, appearances of more than 1 inning have declined nearly every single year. After peaking at about 64%, or nearly 2/3rds of all relief appearances, these days such appearances make up just under 1/3rd.
- As those more-than-one-inning appearances have declined, both of the shorter type have steadily increase in frequency, although it's the appearances of exactly 1 inning that have picked up most of the slack.
- Just think about how much the game has changed. In 1979, about 60% of all relief appearances (non-save) were more than 1 inning, while 25% were less than one inning and 15% were exactly one inning. But in 2009, one-inning appearances were over 40% while both of the other kinds were under 30%. I assume this is due predominantly to the emergence of the 8th-inning setup guy, which just about all teams have now.
There's one other thing to keep in mind here. As long relief appearances decline in frequency, this means that more reliever must appear in each game to make up all the innings that require pitching. I calculated the average number of relief appearances per game (again subtracting out save situational appearances.) Rather the showing the whole graph, I'll just give you a few of the key numbers. From 1954 to 1972, the average number of relief appearances per game (non-save) ranged between about 1.1 and 1.4. In 1973, it plummeted to a post-1954 low of 0.88 per game. Since then it has increased steadily to 1.57 in 1990, then 2.00 in 1996, reaching a post-1954 (and definitely all-time) high of 2.43 in 2009.
January 14th, 2010 at 3:59 pm
Again, very cool plots.
As you are getting more general in your analysis, is there still a reason for excluding save opportunities? I know your original intent was to exclude the 1-inning saves that are so common today but I'd be curious to see how their inclusion affects the plots. Thanks.
January 14th, 2010 at 4:07 pm
Yeah. I know a while back I plotted saves of less than or more than 1 inning, so that data is on this blog somewhere. It probably bears repeating. I also will do the same plot in this post for the NL.
I've been sick with a bad stomach bug so I'm a little backed up (no pun intended.)
January 14th, 2010 at 8:58 pm
http://www.baseball-reference.com/blog/archives/1831
January 14th, 2010 at 9:01 pm
Raphy is the master of finding old blog posts. Thanks again, man.
January 15th, 2010 at 12:32 pm
I understand the need for specialization, and for not blowing out a starter's arm, but is it just me or do today's GMs and managers fail at math? You have the same number of innings to pitch, yet they a) use starters for fewer innings, and b) use relievers for fewer innings. Hence, more relievers, at a time when good middle relief is so hard to find, too. So you eat up more and more roster spaces, and even if it is "just" 11 or 12 on your roster, it's really more, because every team has another guy or two or three shuttling from the minors or on the DL or waiting by the phone for the call (can you hear me now, Jesse Orosco?). In other words, you are eating away at your bench AND relying on more bad pitchers to do so. How is that better than how it was done before?
January 15th, 2010 at 1:16 pm
So does it follow that relievers are pitching the same number of innings, but spread over more games? If so, it seems they'd wear out/tire quicker, as the more appearances they have, the more warm-up pitches they need to throw and the less recovery time their bodies have.
January 15th, 2010 at 2:27 pm
No, they're pitching fewer IP. The 100-IP reliever is all but extinct. I think even 90 IP is pretty rare these days. Most closers don't reach 80 anymore. I'm not sure how accurately the PI can show this trend, because I don't think it can separate relief IP from starting IP, if a pitcher did both in the same season, but perhaps one of our intrepid bloggers will finesse the numbers for us regardless.
January 15th, 2010 at 5:11 pm
Back to the situation of less than one inning - I had previously made the statement that the <1 inning appearance would rise at a similar rate as the 1 inning appearance.
But according to the stats, it appears that since the sharp decline in <1 inning appearances (due presumabley to the DH), the % held roughly steady (up and down) until the late 80's (perhaps due to Larussa style lefty/righty matchups?) where it increased contiunally until the mid 90's (where more teams seemed to adopt the Cito Gaston 1 inning approach as outlined previously in these threads).