How the MLB Draft Works: Rounds, Slots and Bonus Pools
How the amateur draft is built: who is eligible, how the order is set, what a slot value is, how a club's bonus pool limits spending, and how teams trade savings on one pick for extra money on another.
The MLB draft is the annual selection of amateur players from high schools, colleges and junior colleges in the United States, Canada and Puerto Rico. It has run since 1965, and it differs from the drafts in other American sports in three ways that matter. It is long, with 20 rounds as of the 2023 draft. Almost none of the players selected reach the majors quickly, so the payoff for a pick is measured in years. And the money is capped in an unusual way: each club gets a bonus pool to spend on its top picks, and the league penalizes clubs that exceed it.
Understanding those three things, the rounds, the slots and the pool, explains most of the draft-day news you read each July. This guide covers who can be drafted, how the order is decided, how slot values and bonus pools work, how clubs trade money between picks, and what happens after a player is chosen. Rules in this area are set by the labor agreement and have changed before, so confirm details with the league's official site for the year you care about.
What the draft is for
Before the draft existed, amateur players were free agents. Any club could try to sign any young player, and the clubs with the most money or the best relationships could sign the most talent. The draft was created to give every club a turn at the available players and to hold down the cost of signing them. It began in 1965, and the first player chosen was Rick Monday, picked by the Kansas City Athletics.
A draft does two jobs. It assigns each player's rights to one club, so he can negotiate only with that club until the rights lapse. And it sets the order in which clubs choose, which in baseball has historically given the worst records the earliest picks. The extent to which the second job still works, since a lottery now sets the top of the order, is covered below.
Keep one fact in mind through the rest of this article. Baseball players develop slowly. A first-round pick out of college may reach the majors in two or three years if all goes well; a high-school pick may need five or more. The draft is therefore a long-term investment, and the comparison with drafts in sports where a player steps directly onto the roster is misleading.
Who is eligible
A player is eligible for the draft if he lives in the United States, Canada or Puerto Rico and has not yet signed a professional contract. Within that group:
- High-school players are eligible once they have graduated, provided they have not enrolled in a four-year college.
- Four-year college players become eligible after their junior year or when they turn 21 within 45 days of the draft, whichever comes first. A sophomore is generally not eligible.
- Junior-college players are eligible at any time.
Players from outside those places are not drafted. Prospects from the Dominican Republic, Venezuela and elsewhere sign as international free agents, with the signing money limited by a separate system of international bonus pools. The main point here is that the draft is a domestic mechanism.
A player who is drafted and does not sign is not bound. A high-school player who chooses to attend a four-year college instead becomes eligible again after his junior year. A college player who goes unsigned may be drafted again if he is still eligible. That gives a draftee leverage, which is why the pool and the slot values exist.
How many rounds
The draft has had many formats. For years it ran 40 rounds or more, producing enormous classes of players, most of whom never reached the majors. In 2020, because of the pandemic, it was cut to five rounds. Beginning in 2021 it settled at 20 rounds, and it has been held in July in connection with All-Star week rather than in June. With 30 clubs and 20 rounds, there are at least 600 selections, plus extra picks added between rounds.
The shorter draft has an effect on the minor leagues. Fewer drafted players means fewer minor-league contracts to hand out, and clubs sign additional amateurs after the draft as undrafted free agents. The 2021 minor-league restructuring explains how the minor-league system was reshaped at the same time.
How the order is set
The draft is held round by round. In each round, each club picks once, in a set order, and the order of the first round determines the order of all the later ones.
Until a few years ago, the club with the worst record the previous year picked first, the next-worst second, and so on. Since the 2022 draft, the first six picks are set by a lottery among the 18 clubs that did not make the playoffs. The worse a club's record, the better its odds, but a bad record no longer guarantees a top-three pick. The remaining non-playoff clubs then pick in reverse order of record, and the playoff clubs follow. The MLB draft lottery explained walks through the odds and the reasoning, which was to discourage clubs from losing on purpose.
Competitive balance rounds
Two extra rounds are inserted: Competitive Balance Round A after the first round and Round B after the second. These picks go to clubs with smaller markets or lower revenues, and the picks themselves are tradable. That makes them unusual, because apart from them, baseball's draft picks cannot be traded. A club can acquire a competitive balance pick in a trade, but it cannot trade its first-round pick for another team's.
Compensation picks
Other picks are added to the draft in specific cases. A club that fails to sign one of its highest picks can receive a compensatory pick in the next draft. Draft-pick compensation also attaches to certain free agents who turned down a qualifying offer, a system explained in coverage of trades and free agency. Both are extra selections slotted in at fixed spots.
Slot values: the price tag on each pick
Every pick in the first ten rounds, along with the competitive balance picks, carries a slot value, a suggested bonus set by the league and published before the draft. The slot value declines from the first overall pick downward: the player chosen first has the highest, and each later pick has a slightly lower one. It is a guide, not a requirement. A club can pay a player more than his slot, or less, as long as it stays inside its overall pool.
The slot values add up. The sum of a club's slot values for its picks in the first ten rounds, plus the competitive balance picks, is its bonus pool for the draft. A club that holds a high pick has a larger pool, which is one of the ways the draft rewards a bad record.
| Term | Meaning |
|---|---|
| Slot value | The league's suggested bonus for a specific pick |
| Bonus pool | The total of a club's slot values for its picks in rounds 1 to 10 and the competitive balance rounds |
| Overslot | A bonus above the pick's slot value |
| Underslot | A bonus below the pick's slot value |
| Overage | Spending above the pool, taxed and penalized in tiers |
Picks after the tenth round have no slot values, but they are not free. A bonus above a set dollar amount (which the league sets and revises) counts against the pool. The result is that a club cannot sign a late-round high-school star for a large sum without drawing down the money available for the earlier picks.
What happens when a club goes over
The pool is enforced by penalties. A club that exceeds its pool by a small percentage pays a tax on the overage. A club that exceeds it by more pays a higher tax and loses future first-round draft picks. The penalties escalate in steps, and the exact thresholds and rates are in the labor agreement. The harsher tiers include the loss of future first-round picks, which clubs have strong reasons to avoid, so the pool works as a firm limit even though it is not a hard cap.
A worked example
The numbers below are invented to show how the arithmetic works, using units instead of dollars. Suppose a club has a pool of 100 units, made up of these slots.
| Pick | Slot | Signed for | Difference |
|---|---|---|---|
| First-round pick | 40 | 36 | 4 under |
| Second-round pick | 20 | 20 | even |
| Third-round pick (a high-school player with a college commitment) | 12 | 22 | 10 over |
| Rounds 4 to 10 combined | 28 | 22 | 6 under |
| Total | 100 | 100 | even |
The club saved 4 units by signing its first-round pick below slot and 6 units by signing its mid-round college seniors below slot, and it spent all 10 on a third-round high-school player who would otherwise have gone to college. Its total spending equals its pool. This is the logic of an underslot deal: save money on a player who has little leverage and spend it on a player who does. A player who agrees to a discount, usually a college senior with no other options, helps the club, and the club can then afford a high-school draftee whose alternative is a scholarship.
The trade-off is real, because the savings have to come from somewhere. A club that spends heavily on one high-school player may have to take a cheaper, less highly rated player at another pick, and how well a club judges that exchange is a skill that shows up over several drafts.
Signability and the college decision
The draft is not simply a ranking of the best players. Each club considers whether it can sign the player at a price it can afford, a concept called signability. A talented high-school pitcher with a scholarship to a major college program may fall in the draft if his asking price is above the slot, because a club that picks him must pay more or risk not signing him. A college senior has little leverage, because he has no more college eligibility to return to, and he often signs for less than slot.
The decision for the player is not only about money. A high-school player who goes to college can be drafted again after three years and may improve his position, but he also risks injury and a bad year. A college junior can return for his senior year but loses most of his leverage. These choices are the reason draft-day stories include phrases such as "above slot," "committed to" and "signability."
Players have a window to decide. After the draft, the league sets a signing deadline a couple of weeks later. A player who does not sign by the deadline cannot sign with the club that drafted him, and his rights lapse. The club that fails to sign a high pick may receive a compensatory pick in the next draft, and its bonus pool is reduced by the slot value of the unsigned pick.
After the draft
Drafted players sign minor-league contracts and are assigned to the club's lowest levels, usually a complex-league team or a Low-A club, depending on age and experience. The signing bonus is a one-time payment; the salary that follows is small. How minor leaguers get paid covers the pay structure, and how the minor leagues are organized describes the levels a prospect climbs.
A drafted player is not on the club's 40-man roster. He becomes eligible for the Rule 5 draft after a set number of seasons, so the club must decide before then whether to add him to the 40-man roster and protect him. The Rule 5 draft explained describes that next step.
Scouts evaluate draft prospects on a numeric scale from 20 to 80 for each skill, a system described in how scouts grade prospects. Those grades, together with a player's age, injury history and signability, determine where he is picked.
Why the draft is hard
The draft is an inexact science for several reasons. Players are young, and their development is unpredictable. High-school players are more raw and have higher upside; college players are closer to the majors and carry less uncertainty. Pitchers are injury-prone, and a prospect's best skill may not translate to the higher level. A scout can grade a swing but not a player's response to failure. And many draftees never reach the majors at all.
Steve Carlton is a reminder of how old the system is. His big-league career began in 1965, the year of the first draft, and ended in 1988 with 329 wins. He was already in professional baseball when that first draft took place, so he belongs to the older, free-for-all era of signing amateurs.
Common questions
How many rounds is the draft? Twenty, as of the 2023 draft, plus competitive balance and compensation picks.
Can draft picks be traded? Competitive balance picks can be traded. Regular picks cannot.
Why is the draft held in July? Since 2021 it has been held during All-Star week, which gives the college and high-school seasons time to end and puts the draft in front of a national audience. Before 2021 it was held in June.
What is a bonus pool? The total of a club's slot values for its first ten rounds and competitive balance picks. Spending above it brings taxes and, past higher thresholds, the loss of future picks.
Do drafted players have to sign? No. A player can decline and return to school or, if eligible, wait for a later draft.
Who is not eligible? Players who live outside the United States, Canada and Puerto Rico, who sign through the international system, and players who have already signed professional contracts.
Where to go next
The draft is one piece of a larger system that includes the minor leagues, the 40-man roster and the way a club decides whom to promote. How the MLB postseason works covers the other end of the calendar, the October games that drafted players hope to reach, and the minors page tracks affiliated clubs. For news on prospects and the draft, see the MLB draft and prospects topic page, and for the college game that supplies many picks, see the college baseball page.