Instant Replay and the Challenge System in Baseball
How video review reached baseball in 2008 for home runs, how manager challenges began in 2014, what can and cannot be reviewed, and how managers decide when a challenge is worth spending.
Instant replay came to Major League Baseball in two steps. The first, late in the 2008 season, let umpires look at video to settle disputed home runs. The second, in 2014, let managers ask for a review of many more kinds of plays and moved the final decision to a central replay center in New York. Between them those two changes turned a game that had been officiated by eye for well over a century into one in which a close play at first base can be checked frame by frame.
For a fan, the practical questions are narrow. Which calls can a manager challenge? What happens when a challenge fails? Why does the broadcast sometimes show a clear angle and the umpires still say "the call stands"? And why does every manager seem to keep a challenge in his pocket until late in the game? The answers come from a set of rules that are simple in outline and fussy in detail.
This article explains the history, the process, the categories of plays that can be reviewed and the ones that cannot, and the strategy behind using a challenge. It covers the rules in general terms. The league adjusts procedures from time to time, so for anything that depends on a fine point, such as a time limit or a particular category, check the official rulebook or the league's own explanation before you rely on this page.
Why baseball waited so long
Baseball resisted video review for decades, and the resistance had reasons. The game is full of judgment calls that video cannot settle, such as the strike zone, and a sport whose defining plays happen over a base or a plate that can be tagged in a fraction of a second is hard to officiate even with cameras. There was also a cultural argument that umpires were part of the game and that human error was part of its texture. Fans who grew up with a manager kicking dirt on an umpire's shoes did not necessarily want a television monitor to replace the argument.
Pressure built from a series of plays that millions of people saw and that video showed to be wrong. One of the best-known came in the 1996 American League Championship Series, when a young fan in the right-field seats at old Yankee Stadium reached over the wall and deflected a fly ball hit by Derek Jeter. The umpire ruled it a home run. The Baltimore Orioles protested and lost, because the umpires' ruling stood and there was no video procedure to correct it. The play is still shorthand for what the game could not fix.
Boundary calls were the most obvious place to start. Whether a ball cleared the fence, struck the top of the wall or landed foul of the pole is a question of fact that a camera can answer, and the answer does not depend on the umpire's view of the strike zone or of a runner's foot. That is why the first replay system was limited to home runs. It was a cautious step, intended to correct a narrow class of mistakes without changing how the game was run.
2008: replay for home runs
The league introduced instant replay late in the 2008 season. The rule applied to so-called boundary calls: whether a fly ball was a home run or stayed in play, whether it was fair or foul down the line, and whether a fan had interfered with a ball in play near the fence. When a crew chief or the umpires on the field thought a review was warranted, or a manager asked for one, the crew left the field to look at video on a monitor at the ballpark, then returned and announced the decision.
The system made no provision for challenges. A manager could ask an umpire to consider a review, but the umpire decided whether to go to the monitor. Managers had no formal challenge to spend.
In practice, home-run reviews were occasional, and most games had none. They corrected some calls and, more importantly, established the principle that video could overrule an umpire at the highest level. That principle was the foundation for the larger change that followed. The league had shown it would let a monitor override a human decision, and the argument over scope began.
2010 and the perfect game that was not
The case for expanding replay got a powerful push in June 2010. Armando Galarraga of the Detroit Tigers was one out from a perfect game when the batter hit a ground ball to first base. The runner was out by a step on the replay, but the umpire at first base, Jim Joyce, called him safe, and the perfect game was lost. Joyce saw the replay afterward and acknowledged that he had missed the call. The commissioner at the time declined to reverse the decision.
The episode left the game with an uncomfortable fact: the entire audience could see that the call was wrong, the umpire agreed, and nothing could be done. It strengthened the argument that the league needed a way to correct clear errors on plays like this one. Replay at that point did not cover force plays, so even if a review system had existed, a play at first base would not have been eligible.
The details of this episode matter for what came next. They show that the problem the league had to solve was not the home run, which was already covered, but the ordinary close play on the bases and in the outfield, where a mistake can decide a game. The next step was to build a system for those plays.
2014: managers challenge and New York decides
Before the 2014 season the league adopted an expanded replay system. The central change was that managers could now challenge a call by asking for it to be reviewed, and that the review would be decided by officials in a replay center in New York, working from the broadcast feeds and other camera angles gathered at the league office. The umpires at the ballpark would confer with the replay center, usually with the crew chief wearing a headset, and the replay official would give the final ruling.
The rules for challenges in the original system worked as follows.
- A manager starts with one challenge. If it succeeds and the call is overturned, he keeps it and receives a second, so he never has more than two in a game. If it fails, because the call is confirmed or the call stands, he loses it.
- From the seventh inning on, the crew chief can initiate a review. After a point late in the game, the umpire crew itself may ask for a review of a reviewable play, even if the manager has no challenges left. This protects the late innings, where a mistake is hardest to recover from. MLB's current glossary puts the starting point at the eighth inning.
- The manager has to ask promptly. A manager has a short, limited time to signal a challenge after a play, and the league applies it so that the game does not stall while the dugout studies video. Teams employ staff who watch video during the game and tell the manager whether a play is worth challenging.
- The standard for overturning is high. The call on the field stands unless the review shows clear and convincing evidence that it was wrong. If the video is inconclusive, the umpire's original call is kept.
The "clear and convincing" standard is the single most important phrase in the system. It means that replay is not a second umpire starting from scratch. It is a check for obvious error. A play that is too close to judge even with slow motion produces "the call stands," and the original decision is not disturbed. That is why fans sometimes see a clear-looking replay and an unchanged call: the review was looking at all available angles, and no angle gave a view that would meet the standard.
What can be reviewed
The system covers a defined list of plays, and the list is organized by the kind of judgment involved. The table is a general guide, not a rulebook, and the league has changed the details over time.
| Kind of play | Usually reviewable? | Notes |
|---|---|---|
| Home run or not: over the fence, fair or foul | Yes | The original 2008 category |
| Fan interference with a ball near the wall | Yes | Also a boundary call |
| Force play at a base | Yes | Whether the runner or the throw arrived first |
| Tag play | Yes | Whether the tag was applied and whether the runner was on the base |
| Catch or no catch | Yes | Includes outfield trapping plays |
| Fair or foul down the lines | Yes | For balls in the outfield |
| Batter hit by a pitch | Yes | Whether the ball struck the batter |
| Whether a runner touched a base | Yes | Including a runner who missed one |
| Timing plays | Yes | Whether a run scored before the third out |
| Balls and strikes | No | Judgment of the strike zone |
| Check swings | No | The base umpire's judgment |
| Balks and other pure judgment calls | No | Left to the umpire |
Several points need emphasis. The strike zone is outside the system entirely. Whether a pitch was a ball or a strike is the plate umpire's judgment, and the replay center will not look at it. That is a separate technology question, and the league has tested it in the minor leagues through automated ball-strike systems, as described in Automated Ball-Strike Systems: How Robot Umpires Have Been Tested. The definition of the zone itself is covered in The Strike Zone: Its Official Definition, Its History and Why It Is Hard to Call.
A second point is that the system reviews facts, not rules. If the question is whether the runner's foot was on the bag, video can answer it. If the question is whether a pitcher's move to the plate was a balk, the umpire's judgment is involved, and it is not reviewable. The line between a question of fact and a question of judgment is the thing that managers and umpires argue about most.
A play-by-play example of a challenge
A worked example, which is hypothetical and not drawn from a particular game, shows how the pieces fit. The visiting team is trailing by one run in the sixth inning, and its runner is on first with one out. The batter hits a ground ball to the shortstop, who throws to second base for the force, and the second baseman relays to first. The umpire at first calls the batter out, ending the inning on a double play.
The visiting manager sees on the dugout monitor that the batter's foot touched first base before the ball reached the first baseman's glove. He walks to the umpire and signals a challenge. The crew chief puts on a headset and speaks to the replay center. Officials in New York have the broadcast feed from several angles and look at the moment of the catch and the moment of the foot touching the base. The standard they apply is whether there is clear and convincing evidence that the call was wrong.
There are three possible outcomes. If the video shows the foot on the bag before the ball arrived, the call is overturned: the batter is safe, the runner is moved to the correct base, and the inning continues. If the video shows the opposite, the call is confirmed, and the manager loses his challenge. If the angles are inconclusive, the call stands, and the manager also loses the challenge. The manager has to weigh those odds before he walks out.
That decision is a gamble with a small, fixed budget. A challenge can reverse a play that costs the team a run or an inning, but spending it on a play with a low chance of success leaves nothing for later. For a deeper look at how a single out can change the value of an inning, see Is the Sacrifice Bunt Worth It? The Run Expectancy Math, which uses the same logic to price outs and baserunners.
The strategy of the challenge
Managers treat challenges as a limited resource. A challenge is more valuable when the play it could reverse has a large effect on the score, and less valuable when the play is routine. Several habits follow from that.
- Save the first challenge for a big moment. A call that ends an inning with runners in scoring position is worth more than a call on a routine out in the second inning.
- Count on the crew chief late in the game. Because the umpires can initiate a review late in the game, a manager who has spent his challenges earlier still has a safety net for late calls.
- Trust the video staff. The people who watch the replay in the clubhouse have a better angle than the manager in the dugout, and their recommendation weighs heavily. Teams have invested in this role since 2014.
- Know the plays that rarely get overturned. Some calls, such as a very close tag, are hard to reverse because the video is rarely conclusive. A manager who challenges those plays often loses.
- Use the first challenge when the evidence is clear. If the dugout staff is confident, there is little reason to wait, because an overturned call lets the manager keep the challenge and try again.
There is also an element of timing that is not strategic at all. The game's pace depends on how quickly reviews are conducted. Reviews that take several minutes interrupt the rhythm of the game, and the league has tried to shorten them by tightening procedures. The related changes to speed up play are covered in Mound Visits and Pickoff Limits: The Rules That Speed Up the Game and The Extra-Innings Runner on Second.
The collision rule and other companion changes
Replay arrived in 2014 alongside a change in how the game treats collisions at home plate. After a catcher was badly injured in a collision in 2011, the league adopted a rule restricting runners from deliberately running into catchers and catchers from blocking the plate without the ball. Plays at home became reviewable, and the question of whether a runner or a catcher violated the rule was part of what the replay system had to judge. The injured catcher was Buster Posey of the San Francisco Giants, whose career is covered in the best players in San Francisco Giants history.
Another change came after a hard slide at second base in the 2015 postseason that broke an opposing infielder's leg. The league adopted a rule in 2016 requiring runners to make a bona fide slide and not to alter their path to hit a fielder, and it clarified how plays at second base on a double play would be handled. The point is that replay did not exist in isolation. It sat alongside rule changes that were meant to reduce violent plays, and each needed a way to be enforced.
Replay also applies in the postseason, where the stakes are higher, and the details of how rounds are structured are in How the MLB Postseason Works.
Common questions
Can a manager challenge a ball or strike? No. The strike zone is a judgment call and falls outside replay. Automated ball-strike systems were tested in the minor leagues and, beginning in 2026, a separate challenge system for pitches was approved for the majors, but it is a different technology from video review.
What happens if the video is inconclusive? The call on the field stands. The system requires clear evidence to overturn a decision, so a play that cannot be settled by the available angles is left as the umpire called it.
Does a successful challenge cost the manager anything? Not under the original rules. A successful challenge lets the manager keep it and earn a second, while a failed challenge uses it up. Check the current rulebook for the exact limits.
Who makes the final decision? Officials in the league's replay center in New York make the ruling, in consultation with the crew chief at the ballpark.
Why does a call sometimes stay even when the replay looks clear to me? The evidence has to meet a high standard, and a view that looks clear on one broadcast angle can be inconclusive on the frame that matters.
Where to go next
If the idea of technology in the umpiring crew interests you, read about the automated ball-strike systems and the strike zone, then look at the rest of our rules and umpiring topic page. The league's own rule explanations are at MLB.com, and the current rulebook is the authority on any detail that has changed.