The NFL Replay Review System Explained
Automatic reviews, coach's challenges, booth reviews in the final minutes and a standard of evidence that few fans know by name. Here is how NFL replay review works from the first look to the ruling.
A receiver dives, the ball bounces, and for a few seconds nobody in the stadium knows what happened. Then the referee puts a hand to his ear, walks to the sideline monitor or talks into his headset, and the whole building waits. Replay review is one of the few moments in football when the game stops so a ruling can be checked against video, and it follows a set of rules that are more specific than most fans realize.
This guide walks through who can start a review, which plays are reviewed automatically, what the standard of evidence is, what a review cannot do, and why a ruling is sometimes confirmed on the field even though the replay looks suspicious to the viewer at home. The exact details of the system change from time to time, so treat the specifics below as a description of how it generally works and confirm the current rules in the league's official rulebook.
A short history of why replay exists
The NFL first used instant replay in the 1980s, dropped it, and then brought it back in 1999 with a challenge system that has been refined many times since. The reason it keeps being revisited is simple: video can answer certain kinds of questions with near certainty, and football has many of those questions. Did the ball cross the goal line? Did the receiver's foot touch the sideline? Did the player fumble before his knee was down?
Replay is a tool for factual questions. It is much less useful for judgment questions, such as whether a defender interfered with a receiver. That distinction explains almost everything about what the league lets replay do.
Three ways a play gets reviewed
In general, a play can be reviewed in one of three ways.
- Automatic review of certain plays. Some plays are reviewed every time, without anyone asking. These include scoring plays and turnovers, because the stakes are high and the questions are factual.
- A coach's challenge. A head coach can throw a red flag to ask for a review of certain plays. This is limited by the number of challenges available and by rules about when a coach can challenge.
- A booth review in specific game situations. In the last stretch of each half, and in overtime, the replay official in the booth can initiate a review himself, and coaches cannot challenge in that window. The idea is that late in a half the clock matters too much to let one team use a challenge as a tactic.
The first is the safest way to be sure a high-leverage call is right, the second is a tool for coaches to correct mistakes they see, and the third protects the end of each half from being decided by someone who cannot challenge.
Automatic reviews: scoring plays and turnovers
Every scoring play in the NFL is reviewed. When a team scores a touchdown, the league's replay system checks the key facts: whether the ball crossed the plane of the goal line, whether the runner was in bounds, whether the receiver had control. A scoring play that is confirmed stays on the board and the game moves on. If the review finds an error, the ruling is changed.
Turnovers are also reviewed automatically in the same way. That covers interceptions and fumbles that change possession. The replay official works to confirm whether the player had possession, whether the ball hit the ground, whether a runner was down before the ball came out, and whether the recovery was clean.
You will often hear the announcement "the play is under review" for these automatic checks even though the on-field ruling is likely to stand. Most are confirmed in seconds, because the replay official only needs to look for clear evidence of an error, and the review often occurs while the teams are lining up for the next play or kicking an extra point.
Coach's challenges
A head coach starts a coach's challenge by throwing the red flag onto the field. Challenges are limited. A coach receives a set number per game, and additional challenges may be granted if earlier challenges are successful. A successful challenge preserves the count, while an unsuccessful one costs the team a timeout. If a coach has no timeouts left, he generally cannot challenge. The exact count and conditions have changed over the years, so check the current rulebook.
There are important restrictions:
- The coach must throw the flag before the next snap or other start of a new play, so that the review applies to a live ruling.
- Plays that are already subject to automatic review cannot be challenged, since they will be checked anyway.
- Some calls can never be challenged, which we cover below.
A coach has to decide quickly. If a ruling goes against his team, his staff is in his headset: a coach upstairs watching replays and telling him whether the call is likely to be overturned. The decision balances two things. First, is this play worth a timeout and a challenge? Second, is the evidence likely to be clear? A coach who spends challenges on borderline plays will not have them when a critical play arrives. See coach's challenges: rules and strategy for the strategy side.
The booth review
Late in each half, and in overtime, coaches stop being the ones who start reviews. Instead, the replay official in the booth can stop the game to review any reviewable play. He does so by communicating with the referee, who then handles the review.
The rule exists because of timing. Near the end of a half, the clock is both precious and manipulable. If coaches could challenge in that window, teams could use the delay to rest players or set up a play. By giving the decision to a neutral official, the league avoids that and also guarantees that key late-game calls get checked even if a coach has no challenges or timeouts left. It is part of why there is attention on the two-minute warning and late-game clock rules.
What the standard of evidence is
When a ruling is reviewed, the question is not "do you agree with the call?" The question is whether the video shows clear and obvious evidence that the ruling was wrong. Different eras have used different phrases, with "indisputable visual evidence" being the long-standing term. The practical meaning is the same. The ruling on the field stands unless the replay clearly shows otherwise.
This standard does a few things:
- It gives the on-field official the benefit of the doubt, which is why a ruling is often "confirmed" even when the replay looks like a toss-up to viewers.
- It limits the use of replay to correcting clear mistakes, not replacing judgment with a different judgment.
- It keeps games moving, because reviews that don't find clear evidence end quickly.
An illustration, hypothetical but common: a receiver goes to the ground with the ball and it moves slightly as he lands. The on-field ruling is a catch. On replay, one angle looks as though the ball touched the ground and one does not. Without a clear view, the call on the field stands. That outcome frustrates fans who want the best guess, but it follows from a design that depends on clear evidence.
What a review looks at
A review checks facts. Examples of what can be reviewed in general include whether a pass was caught or incomplete, whether a runner was down by contact before a fumble, whether the ball crossed the goal line, whether a player stepped out of bounds, whether a player's foot was on the line, and whether the offense had too many players on the field in specific circumstances. Some penalties are reviewable when they are factual, such as certain issues with the clock or the number of players.
A review also deals with the consequences of a changed ruling. If the ruling on a fumble changes, the replay crew decides where the ball should be spotted and which team has possession. If a catch becomes an incompletion, the clock may need to be reset. The referee announces the result, and the game resumes from the corrected spot.
For a detailed list of what falls on each side, see our guide to instant replay: what can and cannot be reviewed.
What cannot be reviewed
The best way to remember the boundary is this: replay decides facts, not opinions. Most judgment fouls, such as holding, are outside the review process. An official's decision to throw a flag or not to throw one is generally not something a coach can challenge. Pass interference was briefly made reviewable in a single season, and the experiment ended, which shows how reluctant the league is to turn replay into a way to second-guess judgment.
Replay also cannot undo an incorrect whistle that ended the play before something happened. If an official blows the play dead too early, replay cannot award yards the runner might have gained. There are specific rules about how a play is spotted after a premature whistle, and they depend on the circumstances.
Finally, replay cannot be used to look at anything that would require guesswork about intent, such as whether a quarterback was trying to throw the ball away.
How the review is conducted
The mechanics are routine. When a review starts, the referee takes control. He may walk to a sideline monitor, where he watches the same video the replay official sees, or he may talk with the replay official through a headset. The referee is in contact with the league's replay support, and the process is designed so the crew gets the same set of angles rather than hunting for one.
While the review is underway, the broadcast shows replays of the play, and the people at home usually see more angles than the referee does. The referee does not hear the commentators, who sometimes make a call before the official ruling, and he is not watching the television feed in the same way.
When the review finishes, the referee announces the result: the ruling on the field is confirmed, or it is reversed, and he explains what the correct ruling is. If a coach's challenge was involved, the referee also announces whether the team is charged a timeout.
Why reviews sometimes feel inconsistent
Fans occasionally feel that two similar plays got different treatment. There are several reasons this can happen:
- The camera angles differ. One play may have a clean angle that shows a ball crossing the line, and another may be hidden behind a pile.
- The starting ruling differs. The standard of "clear and obvious" means the original on-field ruling influences the outcome. If the first call was a catch, replay needs clear evidence it was not. If the first call was an incompletion, replay needs clear evidence it was a catch.
- The rule has details. The definition of a catch involves control, two feet or another body part, and the act of going to the ground, and each clause matters. Two plays that look the same on a highlight may differ on one of those details. Our guide on what is a catch explains the pieces.
- Rules change. Definitions are adjusted from time to time, so a ruling under today's language may not match an older one.
How the system affects strategy
Replay changes the way teams play. A running back reaching for the goal line knows that a scoring play will be reviewed, so there is less worry about a mistaken ruling in his favor. A coach with one challenge left may decide to save it for a possible late-game ruling. A team protecting a lead in the closing minutes knows the booth will check key plays.
Replay also affects clock management. Reviews stop the clock, so a team that needs time can sometimes benefit from a review, while a team trying to run out the clock may not. The rules are designed to limit that kind of tactical use, and that is one reason for the final-minutes booth system.
What to watch for as a viewer
If you want to follow reviews more closely, a few habits help.
- Listen to the referee's explanation. He usually says which part of the play was reviewed.
- Notice the starting ruling. It tells you which way the burden of proof runs.
- Ask whether the question is factual. If it is a judgment call, replay will not change it.
- Keep track of the coach's challenges and timeouts. You can see how each side is spending its resources.
- Check live scores and the game's play-by-play to see how a reviewed play changed the result.
The short version
- Replay reviews facts, not judgment calls.
- Scoring plays and turnovers are reviewed automatically; coaches can challenge other eligible plays within limits.
- A failed challenge usually costs a timeout, and the number of challenges is limited.
- Late in each half and in overtime, the replay official starts reviews and coaches cannot.
- The standard is clear and obvious evidence, so a close call on the field usually stands.
- Rules and details change over time; confirm the current rulebook for specifics.