The Trade Deadline: What Is Allowed Before and After
How baseball's single trade deadline works, what clubs can and cannot do after it passes, how the old two-step waiver system worked before 2019, and why August 31 still matters for the postseason.
Major League Baseball has one trade deadline. After it passes, clubs cannot trade players with one another until the season is over, though they can still release players, sign free agents and claim players placed on waivers. Before 2019 the system was more complicated: a July 31 deadline ended unrestricted trading, but clubs could still make trades through the end of August if the players involved passed through waivers first. The change to a single deadline was one of the larger quiet shifts in how front offices operate, and it explains a good deal about why the days before the deadline are crowded with deals.
This article explains the current rule in plain terms, what a club can still do afterward, how the pre-2019 waiver system worked step by step, and where the postseason eligibility date of August 31 fits. A caution applies throughout. The exact date and time of the deadline are set by the league each year and the fine print of the rules is revised in labor agreements, so treat this as an explanation of how the system works and check MLB's official announcements for the current details.
What the deadline is, and when it falls
The trade deadline is the moment after which clubs may not complete trades. In recent seasons it has fallen at 6 p.m. Eastern on a day in late July or the first days of August, and the league announces the date in advance. The date moves from year to year as the calendar changes, so there is no single day to memorize. The usual advice for fans is to look up the date each spring, which is what the league publishes on its website.
The rule is about the moment a trade is agreed. In practice, deals reached in the final minutes are often announced after the cutoff, once the paperwork and medical checks are done, which is why you sometimes see trades confirmed late on deadline night. What cannot happen is a new trade being agreed after the cutoff, and the league's own announcement is the final word on any particular deal.
The deadline is a barrier between clubs, not a freeze on rosters. A club can still move players up and down between the majors and the minors, place players on the injured list, designate players for assignment, and release them. Those are transactions inside one organization, or between a club and a player, rather than trades.
What clubs can still do after the deadline
When the deadline passes, the following options remain, and they are the toolkit for the rest of the season.
- Sign free agents. Any player who is not under contract to a major-league organization can be signed. That includes veterans who were released during the season and players coming back from other leagues.
- Release players. A club can release anyone it wants, which makes the player a free agent. The club still owes the remaining salary, but it clears the roster spot.
- Designate for assignment. Designating a player for assignment removes him from the 40-man roster and starts a clock of several days during which the club must trade him, release him or send him outright to the minors. After the deadline, the trade option is unavailable.
- Claim players on waivers. Players placed on outright waivers can be claimed by other clubs, which is a transfer of a contract rather than a trade, and it remains possible after the deadline.
- Move players within the organization. Promotions from the minors, optional assignments and injured-list moves all continue.
An example makes the distinction clear. Suppose a contending club loses a starting pitcher to injury on August 5, after the deadline. It cannot trade a prospect to another club for a replacement starter. It can sign a veteran who was released that week, promote a pitcher from Triple-A, or claim a pitcher another club has put on waivers. Those are real options, and clubs use them every August, but the pool of available talent is narrower than it was on July 30, when every pitcher on a rebuilding team was available in a trade.
The date that still matters: August 31
Although trades end at the deadline, August 31 remains a second important date. To be eligible for a club's postseason roster, a player generally has to be in that organization by the end of that day. A player who joins the club in September, for example by free-agent signing, is generally not eligible for the postseason. There are exceptions that allow a club to replace an injured player with someone who was in the organization on August 31, and the details of those exceptions are in MLB's rules, which are the place to check them.
The result is that the practical cutoff for building a postseason roster is the end of August, not the trade deadline. A club that wants to add a free-agent veteran for a playoff run has until August 31 to do it, and a club that has a player in the minors who might help in October needs to have him in the organization by then.
How the old system worked: two deadlines, one waiver step
Before 2019 there were two stages. Through July 31, clubs could trade players freely, subject to contract rights. This was the non-waiver deadline. From August 1 through August 31, a trade could still happen, but only if the player had first cleared waivers. The deadline had also been set at a different time earlier: for many years it fell in mid-June, and it was moved to the end of July in the 1980s.
The August process worked like this.
- The club places the player on revocable waivers. This tells the rest of the league that the club is willing to move him. The word "revocable" matters: the club can pull the player back if it changes its mind.
- Other clubs may claim him. Claims are awarded by priority. In the August process the club with the worst record in the player's own league had first call, then the next-worst, and so on, before the order moved to the other league.
- If a club claims him, the original club has three choices. It can withdraw the player, taking him off waivers and keeping him. It can negotiate a trade with the claiming club. Or it can let the claiming club have the player for the waiver price, with the claiming club taking on the contract.
- If no club claims him, he has cleared waivers. The club is then free to trade him to any team for the rest of the month.
A player could be placed on waivers more than once, and many were, because a placement costs nothing if the club has no intention of letting him go. The system was a mix of strategy and signaling. Clubs often placed most of their roster on waivers to hide the one they really wanted to move, and rivals sometimes claimed a player they did not want, to block another contender from getting him. A claim that was meant to block was a legal tactic, and it was a constant feature of the August process.
The best-known example of how it could work is the one at the end of August 2017, when the Detroit Tigers traded Justin Verlander to the Houston Astros just before the August 31 deadline, in time for him to be eligible for Houston's postseason roster. It is the kind of trade that the old system allowed and the current one does not.
Why baseball changed it in 2019
The league and the players' union agreed to eliminate the August waiver-trade period, and starting with the 2019 season the single deadline took effect. The argument for the change was that the old system was hard to explain, rewarded gamesmanship over competition, and let clubs keep their options open for another month. The argument against it was that the August window was valuable because it let a club that lost a player to injury respond. The reply to that was that a deadline that actually ends the market is a cleaner contest.
The effects follow from the structure. Deals concentrate in the last days before the cutoff. Clubs that are in a race have to commit to a plan earlier, buying before the cutoff or standing pat. Clubs that are out of contention have only one window to sell, which raised the importance of the "rental," a player on an expiring contract who will leave as a free agent at season's end. The value of a rental depends on what the acquiring club can do with him in the final two months and in October, plus any compensation structure at the end of the contract. The mechanics of that last piece are in the qualifying offer explained.
The single deadline also changed how contenders think about the standings. A club that is two games out on July 25 has to decide whether to buy without knowing what the next six weeks will bring. Small margins decide races, and as of the 2025 season ties for postseason spots are settled by rules applied to the clubs' records rather than by an extra game, which the explainer on how MLB tiebreakers work lays out. The current standings, with games behind and wild-card positions, are on the site's standings page.
What can be traded, and what limits a trade
The deadline is not the only restriction on a trade. Several other rules shape who can be moved before it.
- Contract rights. A player with a no-trade clause negotiated in his contract can refuse a trade, or can limit it to a list of clubs. A player with ten years of major-league service and five consecutive years with his current club has the right to veto any trade under the labor agreement, often called the 10-and-5 rule.
- Draft picks. In general, picks in the amateur draft cannot be traded, with limited exceptions for the extra picks that the league awards to small-market and low-revenue clubs.
- Finances. A trade moves salary from one club to another, and that has consequences for the competitive balance tax. A club near the tax threshold may decline a deal that pushes it over, or may seek one that pulls it under. The explainer on the competitive balance tax and revenue sharing covers the mechanics.
- Roster mechanics. A club must have room on its 40-man roster for any player it acquires, so a trade often requires another player to be designated for assignment.
- Players to be named later. Some trades include a player to be named later. The deal is made at the deadline; the identity of that player is settled afterward according to the terms of the agreement.
Buyers, sellers and the in-between
The deadline sorts clubs into rough categories, and the vocabulary is worth knowing.
A buyer is a club in contention, willing to give up prospects for players who can help now. A seller is a club out of the race, willing to trade veterans for prospects or younger players. A club that is neither, sitting at the edge of the wild-card race, is said to be on the fence, and it may buy at some positions and sell at others. The labels are not official, and a club can change categories from one week to the next as results turn.
What is traded is usually future value for present value. A seller gives up a veteran on an expiring contract and receives minor leaguers whose careers are a few years off. A buyer takes the opposite side of the trade. The question that follows a deadline is not whether the buyer won the trade on day one. It is whether the prospects the seller received become useful major leaguers, and the odds on that are long for any single prospect.
The scale of deadline activity depends on the standings, the number of wild-card spots and the number of clubs that consider themselves in the race. With more teams in the playoff field, more clubs stay in contention longer, and fewer sellers are available. That is a general pattern rather than a number, and it explains why the pool of available players at the deadline varies from one year to the next.
What the fan should watch for
A few habits make the deadline easier to follow.
- Distinguish reports from completed trades. News of a trade appears before the transaction is official. A trade is not final until both clubs and the league have confirmed it.
- Look at the player's contract. The remaining salary and the contract's end date tell you whether the acquiring club is renting or buying.
- Watch the 40-man roster. A trade usually forces a club to clear a spot, and the player who is designated for assignment is often the first sign of what comes next.
- Remember August 31. The window for postseason eligibility stays open after the trade market closes.
The site's page for trades and free agency collects news on completed deals, and the schedule shows how many games remain after the deadline.
Common questions
Can teams trade after the deadline? Not with each other during the season. After the deadline clubs may release players, sign free agents and claim players on waivers, but a trade between two clubs cannot be completed until the season is over.
What changed in 2019? The league eliminated the August period in which players could be traded after clearing waivers. Starting that year there was one deadline.
What is a waiver claim? It is a request by a club to take over a player who another club has placed on waivers. It is a transfer of the contract, not a trade, and the rules for it differ from those for a trade.
Why does August 31 still matter? Because a player generally has to be in an organization by then to be eligible for its postseason roster, with exceptions for replacing injured players.
Does the deadline apply to free agents? No. A player without a contract can sign with any club after the deadline, subject to the August 31 postseason rule.
Can a player refuse a trade? Sometimes. A player with a no-trade clause or with 10-and-5 rights can block a deal, and players without those rights cannot.
Where to go next
For the money side of deadline deals, read the competitive balance tax and revenue sharing explained and the qualifying offer explained, and for what happens when two clubs finish the season with the same record, how MLB tiebreakers work. To watch the market, use the site's trades and free agency topic, and for the official rules and each year's calendar go to MLB.com.