Ran into this interesting discussion on pitch counts and Dusty Baker in the wake of the 124 pitch outing by Carlos Zambrano the other day against the Reds. In Zambrano's last seven starts he's gone 115, 125, 119, 103, 112, 117, 124 - a hefty workload for any pitcher, let alone a 23-year old who you'll be counting on in the years ahead.
I’ve done a bit of analysis on this question in the past as well and tend to believe that it isn't just the number of pitches that's the issue, for example, there is no magic to the number 100. However, running a pitcher out there for innings when he is already fatigued leads to a higher likelihood of injuries as his mechanics break down.
Something that struck me when reading this was the response to the statement that pitcher's in the past had always thrown lots of pitches.
Back in The Good Old Days, if a pitcher blew out his arm, it was back to the farm or the factory for him, and he was forgotten. Nowadays, there's a good chance that modern medicine can fix him up and get him back on the mound. So there's been a change in the way in which pitchers are looked at. Instead of being thought of as disposable commodities, they're thought of more as scarce resources, and more and more effort and thought is put into managing those resources.
To me, this rings true. Just take the case of the Cubs Ryan Dempster. Dempster is a guy who was injured in 2002 at the age of 24 and is just coming back from Tommy John surgery. When you look at his history it's not hard to understand how that happened.
Age Year InningsThat's a pretty big workload for such a young pitcher, almost 1,100 innings before the age of 25. And this especially for a pitcher that both strikes out and walks an above average number of hitters. Dempster's Batters Faced Per Start (BFS) in 2000 and 2001 was 29.5 and 28.1, fairly high totals. He also averaged over 105 pitches per start in those two seasons and 99 as a 23-year old. Had the Marlins been a bit more cautious with Dempster he may not have had the inury problems he's had.
18 1995 40
19 1996 170.67
20 1997 165.33
21 1998 132.67
22 1999 147
23 2000 226.33
24 2001 211.33