How The New 2021 Schedule Will Shake Up Minor League Rotations

Image credit: Hunter Greene (Photo by Bill Mitchell)

Ever since the four-man rotation faded into memory in the early 1980s, professional baseball has revolved around the five-man rotation. Starting pitchers get the ball every sixth day. With few off days during the season, teams can either use the sporadic day off to give everyone an extra day of rest or skip one starter while keeping everyone else on their regular schedule.

In this way, pro baseball in the United States is in a somewhat unique situation. In college baseball, rotations revolve around a seven-day schedule. Starters generally start once a week. That’s generally the case in high school as well. And it’s often the case overseas—in Japan, teams rarely play on Monday, so most starters work on a once-a-week schedule.

This year the minor leagues will be looking at a schedule that is not compatible for using a five-man rotation on regular rest. A few years ago, many minor league teams had one off day a month, which meant that keeping starting pitchers on a schedule where they pitched every fifth day was easy.

This year, every minor league team will be off one day a week—Monday for all but one league while Triple-A West will have Wednesdays off. That means it will be nearly impossible to keep a rotation on a schedule where each pitcher throws every five days.

So what will teams do? Let’s start by trying to keep everyone on a regular schedule. If there’s a day off, everyone’s start is pushed back a day.

So what does that look like? In all the charts below, the number in each row denotes the starter. So 1 equals a No. 1 starter, 2 equals the No. 2 starter, etc.

With this year’s shortened 120-game schedule, all five starters would get 24 starts (which isn’t far off the number of starts pitchers get in a normal 140-game schedule). But only four starts apiece would be on “normal” four days rest between starts.

In essence, this is actually putting every pitcher on a five-day rest cycle with a few (four) starts on short rest. This may prove helpful for teams looking to improve their pitching development, but it will not ensure starters are ready to step into an MLB rotation on short notice.

If trying to keep every starter on normal rest won’t work, what about a system where the starting pitchers at the front of a rotation are kept on schedule, while the back-of-the-rotation starters get their starts skipped to keep the aces on their routine?

Under this system, we get closer to a “normal” schedule. The top four starters all get 25 starts, while the No. 5 starter gets 20 starts.

But you’re still not getting pitchers many starts on four days of rest. The No. 1 starter gets four days of rest between starts 16 times. The No. 2 starter gets 11 starts on normal rest. The No. 3 starter gets five starts on normal rest and the No. 4 starter gets four. The No. 5 starter will get a normal rest between starts this week and then, never more. This hybrid approach is something teams may look at for Double-A/Triple-A, where pitchers need to be ready at a moment’s notice to step into an MLB rotation.

If teams want to keep the majority of their minor league rotations on a regular schedule in a season where teams have an off day every week, they will have to likely adapt to a new paradigm. Teams could adopt a six-man rotation instead, with every pitcher making one start a week.

Under that format, all six starters would make 20 starts in a 120-game season and they would make all their starts on “normal” rest. But in this case the normal rest would be six days of rest between starts.

This likely isn’t something many teams are going to want to adopt at Triple-A, where pitchers are one call away from joining a big league rotation (which is on a five-day schedule). But at the Class A levels, it would mean that college and high school pitchers who are used to a seven-day schedule will remain on that schedule early in their professional careers.

Six starters means that an extra pitcher gets to stretch out as a regular member of the rotation instead of being moved to the bullpen. It also provides potential development benefits, something we will dive into more deeply in an upcoming story.

There are hybrid options where teams could try to blend parts of the various approaches. But it is safe to say the 2021 schedule format will lead to changes in how pitchers are developed.