Pitch Counts

Scott Lemieux directs us to the James/Posnanski colloquy, and Rob Neyer's response. Some thoughts:

• It's almost certainly true that there is nothing special about the 100-pitch limit. The most exhaustive analysis I can recall is Keith Woolner's 2002 articles (Part I, Part II). The punchlines of Woolner's study are (a) the real danger zone starts at around 110 pitches for low-workload pitchers and 130 pitches for high workload pitchers, and (b) yes, Virginia, longer outings do lead to more injuries.
  
• That said, Nate Silver (there's that name again) has done some analysis which shows the age at which pitchers mature is younger than previously thought. Once a starter makes it through age 23, he's probably as healthy as he's ever going to be. Almost every pitcher carries the risk of having their elbow or shoulder fall apart, but it's no greater for a 24 year-old than a 28-year old. If Nolan Ryan and the Rangers are trying to teach 20-year old prospects to throw 130 pitches, that's probably a bad idea, but teaching a 27-year old journeyman to go one more inning is worth doing.
  
• In a semi-related vein, there is no evidence that the five-man rotation improves pitcher effectiveness. This is separate from the question of whether or not the five-man rotation reduces injury risk, for which I have yet to see a rigorous study.
• In addition to the decline in innings pitched by starters, we've also seen a decline in multi-inning relief outings. The long-reliever is basically extinct; instead, managers seem to prefer having a seven-man or eight-man bullpen and let each pitcher throw at full speed for only an inning at a time. While this may allow marginal relievers to be more effective, it forces teams to carry more substitutes who can play multiple defensive positions, which probably reduces offensive potential.

If I were an American League GM, here's how I'd use this information:

• Set a pitch count limit of 95 for any pitcher age 23 and under.
  
• Return to the four-man rotation throughout the majors and minors. This replaces the thirty or so starts by the fifth starter with eight stars from each of the teams' front four pitchers—a significant improvement.
  
• In the low minors, use "paired starters"—two pitchers scheduled for the same day, each of which will throw 85-100 pitches. In the high minors, relax the pitch count limits for older prospects and journeymen, up to 110-115 pitches, or higher for pitchers who can maintain velocity and effectiveness, up to 125-130 pitches.
• Any phenom who makes the major leagues before age 23 has to keep to the pitch limit, perhaps being the "paired starter" with a veteran on his last legs who has to keep to a lower pitch count (think John Smoltz).
• Use the reduction in pitching staff size to bring on a full-time DH. At present, almost every team uses a DH who could play in the field, and on occasion does. Only the Red Sox (Ortiz), White Sox (Thome), and Indians (Hafner) have yet to see their DH take the field, though several teams have near-full time hitters. This should result in a significant offensive boost.
• Replace three one-inning relievers with two long relief men. These pitchers would almost always be called on to pitch in games where one team is significantly ahead or behind, so while they may be less effective because they expect to pitch two or three innings, those innings would likely be in low-leverage situations.
• Keep three or four one-inning fireballers to pitch in close games. Use these pitchers only when one team is ahead by two runs or fewer.

Even if this hypothetical pitching staff had a veteran/phenom pair, it would only have ten or eleven pitchers. That would free up two or three roster slots for more niche position players—a slick fielding shortstop to help preserve a small lead at the end of the game, a speedster to come in as a pinch runner in the late innings, a backup middle infielder who can take some of the stress of the shortstop and second basemen, etc.