Pitcher Abuse Points and Arms Reduction Talks

it's an off-day, so the usual Offday Thread will be going up shortly. However, I also want to update something I posted about on Saturday, concerning the number of pitches thrown by starters. I posted a chart with the number of times AZ hurlers delivered 120 or more pitches in a game, and noted that the number has sharply dropped off of late. On Sunday, I went back and checked the same numbers for the entire National League, so here is a revised version of that chart, adding the NL totals, and the maximum across the entire league:

I did scan the AL quickly, thinking the number of pitches thrown there might be higher because of the DH. But the five most arm-destroying outings since 1998 are all on the Senior Circuit. The most pitches thrown in the American League was 149, by Roger Clemens in May 1998 for Toronto. In the ten-plus seasons covered, only eighteen AL starters have reached 140, compared to thirty-two in the NL. This does surprise me: I'd have thought the reverse would be true, since AL pitchers are immune to being removed for a pinch-hitter. Any suggestions as to why this is the case, are welcome.

The overall figures do tie in with something 'Skins mentioned: an increasing awareness regarding pitcher fatigue and in particular, the concept of Pitcher Abuse Points (PAP). Basically, the way it works is, all starts up to 100 pitches are worth zero PAP. 101 pitches is worth one point; 102 is worth 2x2x2 = eight points; 103 is worth 3x3x3 = 27 points, and so on. Therefore, when you go past 120, the PAP really start to mount. This metric was first published in the Baseball Prospectus annual for 2001. Obviously, word on these things takes time to get around, but is it just coincidence that the number of 120+ games basically halved that year, never to recover?

I also note that the number has collapsed even further last season and this, with the number in 2008 likely to be around 35, less than half of what it was, only in 2006. I found this interesting follow-up, written in 2004, in Baseball Prospectus, where Rany Jazayerli predicted the impact PAP would have on usage patterns. Some of them haven't come to pass - the four-man rotation hasn't returned to use - but he was spot on here: "More careful observation of pitch counts, with most pitchers probably averaging about 90-95 pitches a start, and rarely going over 110 in any given outing. Older, more established pitchers might average closer to 100 pitches a start, with a soft limit of 120 pitches in an outing."

Thus far, the average National League starter has faced almost exactly 25 hitters per game [per here, 35,136 in 1405 starts], with each plate appearance lasting 3.78 pitches on average. Doing the math, that's 94.2 pitches per start, right in the range predicted by Jazayerli four years ago; he also predicted the reduction of the 120+ pitch outing to the level of an endangered species. At this rate, it won't be long before seeing a pitcher throw that many will be entirely a thing of the past, on the level of seeing one make forty starts or throw ten complete games in a year. However, it likely won't become entirely extinct, at least for as long as the Hernandez brothers continue to play!