Fan's Guide to MLB Rules and Replay Review 2026

Under MLB's pitch timer rules, pitchers are limited to two disengagements (pickoff attempts or step-offs) per plate appearance.

• The limit resets if a runner or runners advance during the plate appearance.
• If a third pickoff attempt is made and does not succeed, the runner automatically advances one base.
• With runners on base, the pitch timer resets when the pitcher attempts a pickoff or steps off the rubber.
• Mound visits, injury timeouts and offensive team timeouts do not count as a disengagement.

Source: MLB, Pitch Timer (mlb.com/glossary/rules/pitch-timer).

Under Rule 7.01(b)(2) of the 2026 Official Baseball Rules, each half-inning after the ninth begins with a runner on second base.

• The runner is the player in the batting order immediately before that half-inning's leadoff hitter, or a pinch-runner for him. For example, if the number five hitter is due to lead off the tenth, the number four hitter (or a pinch-runner) starts on second.
• If the player immediately before the leadoff hitter is the pitcher, the runner may be the player before the pitcher in the order.
• The leadoff batter is whoever would have led off the inning without this rule.
• If the automatic runner scores, an earned run is not charged to the pitcher.
• The rule does not apply to Wild Card Series, Division Series, League Championship Series or World Series games, so postseason games are played without an automatic runner.

Sources: 2026 Official Baseball Rules, Rule 7.01(b) and 7.01(g); MLB, Designated Runner (mlb.com/glossary/rules/designated-runner).

• Teams are limited to four mound visits per nine innings. A team gets one extra visit for the ninth inning if it has none left at the end of the eighth, and one more for every extra inning played.
• The coaching staff (including the manager) may make one visit per pitcher per inning without removing him. If the same pitcher is visited twice in one inning, he must be removed from the game.
• Visits by managers and coaches are limited to 30 seconds, starting when the manager or coach has left the dugout and been granted time by the umpire. A visit ends when he leaves the 18-foot circle around the pitching rubber.
• Any manager, coach or player visit to the mound counts, except visits to clean cleats in rainy weather, to check a possible injury, or after an offensive substitution is announced. Normal talk between a player and the pitcher that does not need either to leave position is not a visit.
• If a team is out of visits, the umpire has discretion to allow a brief visit at the catcher's request after a cross-up between pitcher and catcher.

Source: MLB, Mound Visit (mlb.com/glossary/rules/mound-visit).

Since 2023, MLB limits defensive alignments:

• The four infielders must be within the boundary of the infield when the pitcher is on the rubber.
• Infielders may not switch sides, so a team cannot move its best defender to the side of the infield where the batter is likelier to hit the ball.
• The rule does not stop a team from placing an outfielder in the infield or in the shallow outfield grass in certain situations, but it prohibits four-outfielder alignments.

Penalty (from the 2025 season): if there is a violation and the violating player is the first to touch the ball in play, the batting team may accept the result of the play or the batter is granted a free base, which lets other runners advance one base. Before 2025 the choice was the result of the play or an automatic ball.

Source: MLB, Defensive Shift Limits (mlb.com/glossary/rules/defensive-shift-limits).

Under Rule 5.10(g) of the 2026 Official Baseball Rules, a starting or relief pitcher must pitch to a minimum of three consecutive batters, including the batter at bat when he enters, until those batters are put out or reach first base, or until the offensive team is put out. The rule makes an exception for a pitcher who is injured or ill and, in the umpire-in-chief's judgment, cannot continue pitching.

A batter counts toward the three only once his plate appearance is complete, which happens when he is put out or becomes a runner.

MLB also explains that a pitcher who faces one batter to end an inning may be removed, but if he is brought back for a later inning he must still face two more batters, for a total of three.

Sources: 2026 Official Baseball Rules, Rule 5.10(g); MLB, Three-batter Minimum (mlb.com/glossary/rules/three-batter-minimum).

The official strike zone is the area over home plate from the midpoint between the batter's shoulders and the top of his uniform pants (measured when he is in his stance and ready to swing) down to a point just below the kneecap. For a strike call, part of the ball must cross over part of home plate within that area.

The home-plate umpire calls balls and strikes after every pitch has passed the batter. If the batter makes contact with the pitch, it is automatically a strike. The current vertical limits have been in place since 1996.

Source: MLB, Strike Zone (mlb.com/glossary/rules/strike-zone).

• Each club gets two manager challenges to start every All-Star Game and postseason game, and one to start every other game.
• A club keeps its challenge if the replay official overturns any challenged call, and loses it if no calls are overturned. A manager may challenge several reviewable calls within a single play using one challenge.
• Once a club has used up its challenges, it cannot challenge any further play or call in the game.
• The manager holds his hands up immediately after the play. The umpire then starts a 15-second timer, and the manager must decide before it reaches zero or the request is denied.
• The manager must make sure the umpire knows which specific calls he wants reviewed, but need not give his reason.

Source: MLB, Manager Challenge (mlb.com/glossary/rules/manager-challenge).

MLB lists these calls as reviewable:

• Potential home runs: whether the ball left the field, hit the top of a fence or a railing, was touched by a fan reaching over the fence, or was fair or foul.
• Non-home run boundary calls, such as a live ball bouncing out of play or a fielder catching a ball near a stadium boundary.
• Fair/foul calls, only on balls that first land at or beyond the set positions of the first- or third-base umpire.
• Force and tag plays, including whether the runner acquired the base.
• Outfield catches (fly balls or line drives in flight). Infield catches are not reviewable.
• Specified baserunning calls: passing a preceding runner, scoring ahead of a third out, and touching a base.
• Hit by pitch: whether the ball may have hit the player, his clothing or his bat. Whether the ball was in the strike zone and whether the batter tried to avoid it are not reviewable.
• Collisions at home plate, tag-ups, placement of runners after a boundary call, and interference on double plays.

Balls and strikes are not on the list.

Source: MLB, Replay Review (mlb.com/glossary/rules/replay-review).

Yes, in two situations:

• At any time in a game, the crew chief may start a review of a potential home run call without a manager challenge being used.
• Beginning in the eighth inning, the crew chief may review all reviewable calls on his own initiative, or at the request of a manager who has no manager challenges left.

Source: MLB, Replay Review (mlb.com/glossary/rules/replay-review).

All reviews are conducted at the Replay Command Center at MLB Advanced Media headquarters in New York, by replay officials, who are full-time Major League umpires working shifts there as well as on the field.

• Replay officials decide whether to change the call on the field, confirm it, or let it stand because there is no clear and convincing evidence.
• Since 2017 they are expected to decide within two minutes (some exceptions are permitted).
• If a call is changed, the replay official places both clubs where they would have been had the original call been correct.
• If a call is overturned, any decision a manager made after the play that was influenced by the incorrect call is nullified, and the manager may reaffirm or change it.
• The decision is final and not subject to further review. Once review has started, on-field personnel from either club who keep arguing the contested calls or the decision are ejected, and no protest is allowed on a replay official's judgment decisions.

Source: MLB, Replay Review (mlb.com/glossary/rules/replay-review).