The Case for the Four-Man Pitching Rotation

There has been a lot of chatter lately about the possibility of Major League Baseball teams moving to a six-man pitching rotation. The argument in favor is generally that pitchers would be more rested and could go farther into games and would not wear down as much as the season progressed. But, is there a better way that would provide more benefit to teams? Let’s take a look at the benefits of a four-man rotation.

The four-man rotation has not been utilized since the mid-80’s save for the Greg Maddux-led Atlanta Braves staff. Pitching on four days rest has been considered regular rest ever since. Starters just do not pitch as many innings as in the past and it is generally regarded that there is a lack of quality starting pitching available now. So, if there is a lack of quality starters out there, why would teams want to use more of them?

Going to a six-man rotation would give a team’s front-line starters about five fewer starts per season. Do fans want to see Clayton Kershaw or Felix Hernandez every sixth day? Does ownership want to pay Max Scherzer $20 million a season to play less? I say no.

With a four-man rotation, you get your ace out there every fourth day. But, instead of letting him pitch as deep into a game as possible, you limit his innings pitched or have a pitch count. Essentially, a manager would be trying to stay away from TTOP, or Times Through the Order Penalty. Here’s how it works.

TTOP refers to the fact that each time through the batting order for a pitcher, the opposing batters get used to seeing his pitches and as he weakens, batting averages and slugging percentages go up. The following is a breakdown of this phenomenon over the past eight seasons utilizing batting average, on base percentage, and slugging percentage:

First PA vs SP: .247/.310/.393
Second PA vs SP: .260/.321/.417
Third PA vs SP: .271/.332/.444

As you can see, by the time a pitcher faces batters for the third time, batting averages go up by 25 points and slugging percentage is up by over 50 points. It’s easy to see how remarkable no-hitters and perfect games really are with this lack of effectiveness. It’s one thing for a pitcher with good command to set down the first nine hitters in a row, but to repeat it two more times is quite another. Now, taking a look at the slash lines over the same time period for a relief pitcher his first time through the order, one can see how much more effective the relief pitcher will be:

First PA vs RP: .241/.313/.366

The relief pitcher’s stats will show that he will be just as effective as the starting pitcher the first time through the order.

In order to use a four-man rotation, teams would have to construct their roster with two or three swingmen, as we will call them. The swingman would most likely come into play as an extra starter during long stretches without a day off or in the case of a doubleheader. A swingman could also potentially finish the game depending on how far into it the starter pitched. If a starter were limited to six innings or 60-70 pitches, the swingman could possibly go the last three innings. However, in the typical game, a swingman would just be a bridge to the short relievers. Using four starters and three swingmen would still leave room for two specialty relievers, two set up men, and a closer on a typical roster.

Obviously, by using their staff in this manner, a team would be more likely to get more out of its number one and two starters and could possibly only be worried about getting five innings out of the third and fourth starters. This would also eliminate the struggle most MLB teams have trying to find a serviceable number five starter, and would allow teams to introduce young pitchers by keeping them away from batters the third time in the game or using them as swingmen.

The two strongest starters on a team could be used to make more starts with fewer pitches for each start. The team’s third and fourth starters could also be alternated with swingmen to allow for more rest and better utilize the staff as the season goes along. Extra innings for the bullpen pieces could also be made up by using call-ups from the minor leagues to give short spells for relief pitchers.

Piling up lots of pitches is obviously one of the main risk factors when it comes to pitching injuries. This is probably one of the factors that was considered when the move was made to go from a four- to a five-man rotation. By using the modified four-man rotation here, pitch counts would remain low and pitchers would be used in more effective situations during games. I would prefer to see it done as a pitch count, rather than innings pitched. It all comes down to pitch efficiency that will determine how far a pitcher goes into the game.

The trend recently has been for teams to spend big money for the back-end of their bullpen in order to take the game away from their opponents in the seventh, eighth, and ninth innings to effectively shorten the game. This four-man rotation would enable teams to utilize their most prized assets more often and with greater chance of success. Going forward in 2015, would the New York Yankees rather get four extra starts from Michael Pineda or have Adam Warren on the hill for those starts? Nothing is guaranteed on a nightly basis, but the law of averages points to the greatest likelihood of sustained success over the long haul here.

Does the five-man rotation exist because of free agency? And has this only made teams become more protective of their expensive investments? Maybe even to the point of being over-protective? Injury concerns were most certainly a factor in the move to a five-man rotation. But the truth is that using this modified four-man rotation could get ace starters on the mound more frequently, and with the lower pitch count and better utilization of bullpen pieces, could produce better all around pitching performances. Everything exists for a reason, but not everything exists for a good reason.

One Response

  1. Bob Jones

    I agree with your ideas completely. A few days ago I took the 2018 Detroit Tigers schedule and set up a four-man rotation using these two rules: no starter pitches on three days rest twice in a row, and no starter goes more than six innings. The first rule can be obeyed by inserting a fifth starter eight times in the season to jog the rotation. Here are the results for the five starters showing starts and starts on three days rest. #1, 40/15; #2, 39/15; #3, 38/13; #4, 37/11; #5, 8/0. The four best arms get the ball many more times than they do now. And, with the 6-inning limit, like you also suggest, pitch counts will be kept down. Etc. I don’t see why you wouldn’t want to put your best players in the game as often as you can. Wouldn’t that increase your chances of winning more games? But what do I know? I’m just a fan.


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