Why are modern pitchers so fragile? They pitch fewer innings per game, start fewer games, and have more days rest between starts. In addition they have much better training and medicine to cope with the stresses of pitching.
I have heard it repeated that there will no longer be 300 game winning pitchers. What happened to the Nolan Ryans and the Bob Gibsons?
Unfortunately, I don’t have very good data to examine exactly how total pitches thrown have changed going too far back in time. But, given the pattern going back to the late-1980s, I think it’s safe to assume that the extreme loads of pitchers are declining, even though the average pitching load has remained constant at about 99 pitches per game.
Using some simpler measure of workloads, innings pitched, the pattern is interesting. The figure below shows the change in total innings pitched in a season over time for the maximum number of innings pitched, and by 95th and 75th percentiles, and the median (minimum 10 games started).
Though there has been a general decline in pitcher workloads over time, there was a bump in the late-1960s and early-1970s, when pitching loads increased over what they where in the 1960s. Since 1962, when the leagues both started playing 162 games a season, there have been 65 pitcher-seasons with 300 or more innings pitched. The last one occurred in 1980 when Steve Carlton threw 304 innings. Below are a table of the number of 300-inning performances by seasons and a list of those performances by pitchers.
Year Count 1962 1 1963 3 1964 1 1965 2 1966 4 1967 1 1968 4 1969 9 1970 4 1971 4 1972 4 1973 7 1974 8 1975 4 1976 2 1977 4 1978 1 1979 1 1980 1 Total 65
Pitcher Year IP Vida Blue 1971 312 Bert Blyleven 1973 325 Jim Bunning 1967 302.33 Jim Bunning 1966 314 Steve Carlton 1980 304 Steve Carlton 1972 346.33 Jim Colborn 1973 314.33 Larry Dierker 1969 305.33 Don Drysdale 1965 308.33 Don Drysdale 1962 314.33 Don Drysdale 1963 315.33 Don Drysdale 1964 321.33 Bob Gibson 1968 304.67 Bob Gibson 1969 314 Dave Goltz 1977 303 Bill Hands 1969 300 Catfish Hunter 1974 318.33 Catfish Hunter 1975 328 Fergie Jenkins 1968 308 Fergie Jenkins 1969 311.33 Fergie Jenkins 1970 313 Fergie Jenkins 1971 325 Fergie Jenkins 1974 328.33 Randy Jones 1976 315.33 Jim Kaat 1975 303.67 Jim Kaat 1966 304.67 Sandy Koufax 1963 311 Sandy Koufax 1966 323 Sandy Koufax 1965 335.67 Mickey Lolich 1974 308 Mickey Lolich 1973 308.67 Mickey Lolich 1972 327.33 Mickey Lolich 1971 376 Juan Marichal 1966 307.33 Juan Marichal 1963 321.33 Juan Marichal 1968 326 Sam McDowell 1970 305 Denny McLain 1969 325 Denny McLain 1968 336 Andy Messersmith1975 321.67 Phil Niekro 1974 302.33 Phil Niekro 1977 330.33 Phil Niekro 1978 334.33 Phil Niekro 1979 342 Claude Osteen 1969 321 Jim Palmer 1970 305 Jim Palmer 1976 315 Jim Palmer 1977 319 Jim Palmer 1975 323 Gaylord Perry 1974 322.33 Gaylord Perry 1969 325.33 Gaylord Perry 1970 328.67 Gaylord Perry 1972 342.67 Gaylord Perry 1973 344 Steve Rogers 1977 301.67 Nolan Ryan 1973 326 Nolan Ryan 1974 332.67 Bill Singer 1969 315.67 Bill Singer 1973 315.67 Mel Stottlemyre 303 1969 Luis Tiant 311.33 1974 Wilbur Wood 320.33 1974 Wilbur Wood 334 1971 Wilbur Wood 359.33 1973 Wilbur Wood 376.67 1972
Thus, it seems that teams tried to ramp up pitcher workloads just prior to the modern decline. What happened in the 1960s and 1970s that caused an increase in pitcher workloads? Did teams realize the ramp-up was a mistake, which caused the trend to reverse? This was an era of low offense, and the mound was lowered and the designated hitter added as a response. Was there a shift in pitching philosophy or did something structural cause this shift? I’m open to suggestions. The bump may offer a clue.
Aside from the bump, what has caused the declining trend in workloads? Most obviously, the rise of the five-man rotation gave pitchers fewer games to cover. On top of this, teams began to rely more on relievers within games pitched than in the past, going with fresh pitchers in late innings rather than asking starters to pace themselves. The number of complete games has declined continuously since the late-1970s.
I think the decline in pitching loads is less a response to a toughness of pitchers than it is a change in pitching philosophy. Every year, someone is supposedly going to go to have four-man rotation, but then we never hear any more about it. Whether that is because no manager has the guts to stick to a plan that is easy to criticize when injuries that were bound to happen anyway happen, or because the five-man rotation actually leads to better pitching, I don’t know. I have found that days of rest appear to have little impact on performance, so I don’t believe there is any performance benefit from giving pitchers more rest days in a five-man rotation. I’d love to see a team go with a four-man rotation from start to finish.
As for the increased use of relievers, I believe managers have discovered that 100% mediocre arms can be more effective than paced good arms. Teams can increase their chances of winning by going to the bullpen, exploiting match-ups, and pinch-hitting for pitchers. Furthermore, I’ve found some evidence that fewer pitches per game can improve future performance among starters.
In summary, my best guess is that the decline in pitching loads is part fad (four-man rotations) and part innovation (relievers can be better than paced starters).
UPDATE: In my initial cut and paste of the 300-inning pitchers I accidentally left off six seasons at the bottom of the table. I have added the missing seasons.