Gil Hodges is credited or blamed, depending on one's point of view, for initiating the five-man pitching rotation in 1969.
Hodges decided to give Tom Seaver, Jerry Koosman, Gary Gentry, Don Cardwell and Jim McAndrew an extra day's rest during the final month of the season.
The reasoning was that an extra day of rest would cut down on arm injuries as well as extend some pitchers' careers. Expansion in 1993 diluted the level of talent, which led to even more care of young, talented arms.
When the Mets won the 1969 World Series, other managers followed Hodges' lead. By the 1980s, all teams favored having a five-man starting rotation. The only exceptions to a starter having four days’ rest occurred during the playoffs or World Series.
Bob Brenly was questioned in 2001 when he started Curt Schilling on three days’ rest against the New York Yankees. Jack McKeon was questioned when he started Josh Beckett against the Yankees on three days’ rest. Sadly, for Yankees' fans, both Schilling and Beckett won.
In 1995, there was a short-lived attempt to return to a four-man rotation which failed to take hold.
Pittsburgh Pirates' manager Jim Leyland and Kansas City Royals' skipper Bob Boone decided to go with a four-man rotation. They were motivated in part because in 1994, a strike-shortened season, 122 pitchers had been placed onto the disabled list. Those who espoused "work prevents sore arms" had renewed influence.
"I think baseball in general babied pitchers' arms too much," Leyland said. "The arm is like any other muscle—the more you use it, the stronger it gets. We used to have four-man rotations all the time years ago. I don't know why it can't work today."
Boone had some doubts.
"I just don't know if I'll have the guts to stay with it," he said. "It's not really my decision. It will be what their arms tell us."
Any chance of a return to giving starters four days rest was lost when the awareness of performance enhancing substances occurred. Pitchers had to extend themselves more because it became more difficult to retire hitters who were making themselves more dangerous.
With a five-man rotation, pitchers get about 33 starts, which has decreased the number of 20-game winners. The long-range consequence is that it is unlikely there will be anymore 300-game winners.
An unanswered question remains. How does pitching on four days of rest affect a pitcher’s longevity?