How Teams Develop Pitchers in the Minors

By 4Baseball Staff · November 5, 2026 · 10 min read

How clubs turn drafted arms into major-league pitchers: the minor-league ladder, workload limits, building a third pitch, the numbers scouts watch and why so many promising pitchers stall.

A drafted pitcher does not arrive in the majors as a finished product. He arrives in a rookie-level complex in Arizona or Florida with a good fastball, perhaps a decent breaking ball, a college or high school workload that his new club needs to understand, and a long list of things to fix. Over the next two to six years the club will try to add a pitch, sharpen his command, build his stamina without hurting his arm, and decide whether he is a starter or a reliever. Most of the time the effort does not work. The ones for whom it does end up on a major-league mound.

This article describes that process: the minor-league ladder, how workloads are managed, how pitches are built, what statistics clubs actually watch, and why the odds are long. It is based on how development is generally described by clubs and by baseball writers. Clubs treat many of their internal methods as trade secrets, so the details vary from organization to organization and we avoid stating any club's rules as fact. The historical record carries only major-league (and early Negro leagues) data, so there are no minor-league statistics in this article.

The ladder: five steps from the draft to the majors

Since the minor leagues were reorganized ahead of the 2021 season, each major-league organization has a defined set of affiliates. The levels, from lowest to highest, are the complex leagues (rookie-level leagues in Arizona and Florida) plus a Dominican Summer League for many clubs, then Single-A (also called Low-A), High-A, Double-A and Triple-A. A club's player development staff moves pitchers up when they have shown they can handle the competition, and sometimes holds them back.

Double-A is often described as the most meaningful test, because the hitters are good enough to take advantage of any weakness. A pitcher who can get Double-A hitters out with a fastball alone is rare; one who cannot is common, and the club has to decide whether he can learn the rest.

The draft is the main pipeline. Since 2021 the draft has run 20 rounds, and players come from high school, junior college and four-year colleges. High school pitchers are usually 17 or 18 and have thrown far fewer innings, which gives the club room to build their workload but means they need years. College pitchers are usually 21 or 22 and have thrown a lot in organized competition, so clubs often limit them early to protect the arm. International signings, who often start in the Dominican Summer League at 16 or 17, follow a similar path from there.

Workload: the arithmetic of protecting an arm

The central risk in pitcher development is injury. Throwing a baseball overhand at high velocity places stress on the elbow and the shoulder. The elbow's ulnar collateral ligament is the best-known weak point; surgery to replace it, known as Tommy John surgery after the pitcher who first had it in 1974, is now common enough that most fans know the name. Because the ligament can fail without much warning, clubs try to control how much stress a young pitcher accumulates.

The tools are simple, and every club uses some version of them.

• Pitch counts. A young starter may be limited to a set number of pitches per outing, and the limit rises through the season and across levels. The numbers differ by club and are not published, so be skeptical of any figure presented as a standard.
• Innings limits. Many clubs set a target for total innings in a season, especially for a pitcher coming off a heavy college workload or a first full professional year.
• Rest days. Some organizations use six-man rotations in the minors so that each starter gets an extra day between outings.
• Tandem or piggyback starts. Two pitchers may split a game, each throwing a limited number of innings. This lets a club give more pitchers regular work while holding each one's workload down.
• Shutdowns. After a draft, a college pitcher who has thrown many innings in the spring is often given a rest period or limited to a few short outings.

One popular rule of thumb deserves a caveat. In the 2000s, writer Tom Verducci popularized the idea that a young pitcher whose innings jump by a large amount from one year to the next, commonly cited as more than about 30, is at higher risk of injury or decline the following year; it became known as the Verducci Effect. Clubs paid attention to it, but later studies did not consistently confirm it. The honest summary is that research on workload and injury is still developing, and clubs' approaches are best understood as reasoned caution, not settled science.

One more point: the same caution costs something. A pitcher who is protected too carefully may never build the stamina to throw 180 innings in the majors. Development staff are balancing two risks, and different clubs weigh them differently.

Building the arsenal

Most drafted pitchers have one plus pitch, usually a fastball. A major-league starter generally needs at least three effective pitches so that hitters cannot sit on one. The typical progression looks like this:

1. Fastball command. Before anything else, the pitcher must locate his fastball, in and out and up and down, because it sets up everything else.
2. A breaking ball. A slider, curveball or sweeper that gets swings and misses and that he can throw for strikes. Our guide to the slider, the sweeper and the cutter explains how these pitches differ.
3. A changeup. A pitch with a speed difference and some fade, used mostly against opposite-handed batters. It is often described as the hardest pitch for young pitchers who rely on a hard fastball, because it requires trusting a pitch that feels slow and soft.
4. Refinement. Adjusting the shape, speed and location of each pitch so that it plays against different kinds of hitters.

Modern development leans heavily on measurement. High-speed cameras and tracking devices record velocity, spin rate, the direction of the spin and the way a pitch moves. Coaches use that information to change a pitcher's grip or release point, then check whether the result moves the way they want. A curveball that spins on the right axis can look completely different to a hitter from one that spins on the wrong one, and it is easier to see that with data than with the naked eye. The tools are common across organizations; what differs is how clubs use them and how many resources they put into the work.

Two vocabulary points help when you read scouting reports. Control is the ability to throw strikes. Command is the ability to put the ball where you want it within the strike zone and just outside it. Stuff is the quality of the pitches themselves: velocity, movement and deception. A pitcher with great stuff and poor command can get lucky for a while; a pitcher with average stuff and excellent command can succeed for a long time. Development usually aims to improve command first, because it is the most useful trait to have when the hitters get better.

What clubs actually measure

Scouts still watch pitchers, but clubs also use statistics to judge progress. The numbers below are standard, and you can find most of them on minor-league stat sites.

FIP stands for fielding independent pitching. Its formula is 13 times home runs, plus 3 times walks and hit batters, minus 2 times strikeouts, all divided by innings pitched, plus a constant (about 3.1 in recent seasons) that puts the number on the same scale as earned run average. Here is a worked example. A pitcher throws 60 innings with 70 strikeouts, 20 walks, 3 hit batters and 4 home runs. The top of the formula is 13 times 4 (52) plus 3 times 23 (69), minus 2 times 70 (140), which is negative 19. Divide by 60 to get negative 0.32, then add the constant, about 3.15: the FIP is roughly 2.83. A pitcher with these numbers is doing the things pitchers control well.

Why use FIP and not earned run average? Because over a small number of innings, ERA depends heavily on defense and on luck with balls in play. In the minors, where defense can be uneven and the samples are small, a pitcher's strikeout and walk rates are a more stable guide to his true skill than his ERA is.

Context matters too. A 22-year-old in Double-A is facing hitters who are, on average, older and more experienced, and a 22-year-old in High-A is not. Age relative to level is one of the first things evaluators check: a young pitcher who does well against older competition usually receives more credit than an older one who beats up on younger hitters.

Starter or reliever?

Almost every pitcher begins as a starter, because starters are more valuable and clubs want to give them every chance. Sooner or later each pitcher gets a verdict. Several things push a pitcher toward the bullpen.

• He lacks a third pitch that he can use against both left-handed and right-handed hitters.
• His command breaks down the third time through the lineup, when hitters have seen him twice.
• He has had arm trouble, and the club wants to limit his innings.
• His stuff plays up in short bursts, with a faster fastball and a sharper breaking ball than he can sustain over six innings.

A conversion to relief is not a failure. Many valuable major-league relievers were failed starters in the minors. What the move often does is shorten the path to the majors, because a bullpen role requires fewer pitches and less stamina. What it costs is the higher value of a starting pitcher. Clubs sometimes move a pitcher to the bullpen as a way to get him to the majors and later try to stretch him out again.

Rules tested in the minors

The minor leagues also serve as a laboratory for rule changes that later reach the majors. The pitch clock, limits on pickoff throws and changes to the size of the bases were all tried in the minors before being adopted in the major leagues in 2023. Each of these affects pitchers directly: a pitch clock changes a pitcher's rhythm and recovery time between pitches, and a limit on pickoffs changes how he holds runners. Our article on what minor league rule experiments taught MLB covers the details and the results.

Why so many promising pitchers fail

The odds are long for several reasons.

1. Injuries. An arm injury can cost a year or more, and surgery does not always restore the pitcher's previous velocity or command.
2. Plateaus. A pitcher may improve quickly in his first two years and then stop. Hitters at higher levels adjust, and a pitcher who cannot change is exposed.
3. Competition. Every organization has more pitching prospects than roster spots. A pitcher who is good but not good enough stays in the minors or is released.
4. Roster rules. Players eligible for the Rule 5 draft who are not on a club's 40-man roster can be selected by other clubs, so a prospect's path may change because of roster math and not performance.

These realities explain why scouting and drafting are so imprecise. Our article on the 2002 draft and what Moneyball got right and wrong looks at how clubs have tried to improve their odds, and the first amateur draft in 1965 shows how long the draft has been the starting point for most careers. Position players follow different timelines; compare how teams develop hitters and why catchers take longest.

How to follow a pitching prospect

If you want to track a pitcher's progress, a few habits help.

• Look at strikeout and walk rates, not just earned run average.
• Note the level and the pitcher's age relative to that level.
• Check innings: a pitcher with a high strikeout rate over 40 innings has told you less than one who does it over 120.
• Watch for changes in velocity or in the number of pitches thrown; a drop in either can signal trouble.
• Treat a hot month with caution; samples in the minors are small.

Our minor league pages and the draft and prospects topic page collect results and news so you can follow along.

Common questions

How long does it take a drafted pitcher to reach the majors? It varies widely. College pitchers often take less time than high school pitchers, but many never arrive, and some take a long path with detours through the bullpen. Treat any single figure as an average over a very varied group.

Do all minor-league pitchers have pitch limits? Most clubs use some form of limit, especially for younger or recently drafted pitchers. The specifics are internal and differ by organization.

Is Tommy John surgery a sign a pitcher is finished? No. It is a serious operation with a long recovery, but many pitchers return to the majors. Outcomes vary, and no article can predict an individual's.

What is a "plus" pitch? In scouting language, a plus pitch is one rated above average on the 20-to-80 scouting scale. Scouts use 50 for average, so a 60 is plus and a 70 is well above average.

Why do clubs move pitchers to the bullpen? Usually because the pitcher lacks a third effective pitch, struggles to hold his stuff over many innings, or has had injury trouble.

Where to go next

Compare the pitching path with the hitting path in how teams develop hitters, and browse the minors section for current results. For the other side of a prospect's career, once he reaches the majors, see the qualifying offer explained.