How does pitching rotation work in baseball

Strikingly delineated are the different pitching rotation eras. Upticks in two-man usage in and led to six years of prevalent use. From to the three-man won the day, and from to , a period of twenty-seven years, the four-man won the plurality despite never exceeding forty-six percent of all starts. In , the five-man was used in over 80 percent of all starts for the first time in history. For any non-SABR members who might be reading this, it should be pointed out that from its origins, baseball was played by nine men on a team.

A tenth man could fill in at any of the nine positions—including pitcher—should one of the starters have a hangover, a funeral to attend, or a court date.

The general exertion for a pitcher in this era was compatible to a modern, medium paced, softball pitcher. Days-of-rest has never been satisfyingly calculated because virtually all pitchers, at one time or another, sit out a few starts. Upon their return, player and team days-of-rest are skewed off chart.

Buffalo in has the lowest ROT figures in the majors yet ranks high in days-of-rest because pitcher Pete Conway sat 79 days before his August 10 start. ROT data provides a unique back-door solution to the days of rest problem.

A five-man rotation means pitchers sit out four games between each start. If we know the average calendar days necessary to play four games, we have our days-of-rest formula. See Figure 2. As it turns out, National Association days-of-rest was more reasonable than many would think. In the average team played a schedule of 28 championship games in calendar days.

In , for the first time, there were more games played during a season than there were off-days, and this trend, combined with an apparent rise of fast ball pitching in , were likely the driving forces in the origin of pitching rotations. But it was the advent of the International Association in that brought real change. This league condoned higher-arm fastball pitching and saw a number of teams hand 20 percent of their starts to secondary pitchers.

In the two made Springfield the first team to score a 1. Manager Robert Ferguson became ill in June but his replacement, Lipman Pike, kept the two pitchers alternating. In the National Association, Springfield disbanded September 6, ten days after their last regular season game.

Corcoran and Goldsmith were signed by the Chicago Nationals within a month. More regular Corcoran and Goldsmith alternation in gave Anson the second of three straight pennants and a never-before-seen ROT of 1. Identifying the Chicagos as the first team to use the pitching rotation is probably not news to SABR membership. Jim Mutrie assembled the strictest two-man pitching rotations. His pennant winning AA Metropolitans used it in 87 percent of their games, a mark topped only by his New York Nationals, who used it 93 percent of the time.

This included one stretch where Tim Keefe and Mickey Welch alternated for a record 44 consecutive games. The three-man came into use when season schedules incrementally expanded, putting pressure on two-man staffs. Major league schedules at that time called for only 84 games. In the three-man entered the NL as an option for second division teams with untested pitching prospects, and to this day, out-of-contention clubs will often add a pitcher to their rotations at the end of the season.

In , both Baltimore and Toronto used six-man September rotations. As noted by Rickert, six-man use actually spiked in as more teams were out of contention than in any other season. This had the effect of bringing meDOR for both leagues to over four days of rest per pitcher for the first time in history. Comparing to , Association days-of-rest dropped from to while three-man cycles doubled from to Three AA teams come close to its first committed use this season.

Louis and Brooklyn almost pull it off, but both use the two-man for extended periods. Stovey, however, spent chunks of the season trying to work an archaic rotation. They had the earliest Spring commitment to the three-man and the necessary depth to make it work. Teams of that era with strong pitchers like Bob Caruthers and Dave Foutz universally forced them into two-man tandems. The three man continued to be a tool of the major league manager until It proved, once and for all, the fallacy of winning with a three-man.

Watkins would abandon Indy and the Western League and sign to manage Detroit, bringing along with him a gaggle of Western League players. Alas, Watkins discarded the rotation and used hunches to pick from his pool of pitchers the rest of the season.

He turned a two-man staff into a three-man and, in the final games of a September home stand, leaned primarily on a four-man rotation. The team won 7 of 10 forcing Baltimore into the cellar. The following year, in , Ferguson had to open the season without staff lynchpin Jack Lynch.

Ferguson used a in the early going: Al Mays was the strong arm while pikers Ed Cushman and John Shaffer alternated on three games of rest.

When Lynch finally joined the team on May 20, Ferguson switched to the four-man, but it was too late. The Metropolitans were in last place and Ferguson was fired ten days later. The problem with implementing a four- or five-man rotation in the nineteenth century was insufficient pitching depth.

To put it in a modern context, nineteenth century managers who dabbled with rotation use actually believed Duane Kuiper, on ten days of rest, could beat Steve Carlton on three days of rest.

Yet early teams not only discarded pitchers after failure—they discarded the entire rotation idea. A graph of league adjusted ROT and team winning percentage for —, the first 1, teams of major league history, displays no reward of success for teams who pushed the envelope of longer rotation use.

See Figure 3. This goal was met in 76 percent of their schedule by tacking on fourth starters for fifty games. Brooklyn became the first team to crack the 3. A poor season finish led to an apparent abandonment of the policy the following year.

If only they had checked their own game logs: a 1—2. A pitcher is credited with a game started if he is the first pitcher to throw a pitch for his team in a given game. A starter who pitches a full season in a five-man rotation will generally tally at most 34 games started. There is no minimum innings plateau for a pitcher to earn a game started, but a starter must pitch at least five innings to be eligible for a win. Beginning in , teams started experimenting with the idea of using an "opener.

No left-hander. Just a dynamic top three, each of whom presents a different look from the next. A phenom flamethrower with a wicked repertoire, a fastball-curveball southpaw and a pitcher's pitcher coming into his own.

Detwiler's terrific start is promising, and Haren has picked it up lately. This may be the best group in baseball, especially with the ideal righty-lefty rhythm. Apologies to Cueto and Latos, but neither is a true No.

Bailey has finally found it, so he fits well in the middle. The rookie Cingrani the sole southpaw has been too good to be true in his first three starts.

The consummate fifth starter. Possibly the deepest set of arms, as Leake could find himself on the outside looking in once Cueto is off the DL. Doesn't get much better than Wainwright as a horse. Fellow veteran Westbrook, somehow currently leading the NL with a 1.