Section 5: Rules of Play
5.1 Starting the Game (OBR Rule 5.01)
Per OBR Rule 5.01, the home team takes the field and the visiting team sends its first batter to the plate to start the game. Before the game starts, the umpire-in-chief calls "Play" to begin. The pitcher must pitch to the first batter within the time limits of the pitch clock (see Rule 5.07(c)).
5.2 The Pitch Clock (OBR Rule 5.07(c)) — Effective 2023
Beginning with the 2023 season, MLB implemented a mandatory pitch clock under OBR Rule 5.07(c):
- The pitcher must begin the pitching motion within 15 seconds of receiving the ball from the catcher (or when the pitcher is otherwise ready) when no runners are on base.
- The pitcher must begin the pitching motion within 20 seconds when runners are on base.
- The batter must be in the batter's box and "alert to the pitcher" with at least 8 seconds remaining on the clock.
- Violation by the pitcher: An automatic ball is added to the count.
- Violation by the batter: An automatic strike is added to the count.
- A pitcher may disengage (step off the rubber) up to two times per plate appearance without penalty; a third disengagement that does not result in an out or advance restores the limit to two on the next disengagement.
5.3 Pitching (OBR Rule 5.07)
Per OBR Rule 5.07(a), the pitcher must take the pitching position by standing on the pitcher's plate in one of two legal positions:
- The Windup Position: The pitcher faces the batter, with the pivot foot in contact with the pitcher's plate and the other foot free.
- The Set Position: The pitcher stands facing the batter with the pivot foot in contact with the pitcher's plate. The pitching hand and glove hand must be brought to a stop ("set") before delivering the pitch.
Per Rule 5.07(b), the pitch is considered delivered when the pitcher's arm passes the hip in the forward swing. Illegal pitches (e.g., a pitch delivered from an illegal position, a quick pitch, or a pitch while in an illegal position) result in a ball being awarded to the batter, or, with runners on base, a balk.
Per Rule 5.07(d) — Pitcher Limits (Three-Batter Minimum): A pitcher (other than a starting pitcher) must face a minimum of three batters, or the remainder of the inning (whichever comes first), unless the pitcher sustains an injury or illness that, in the umpire-in-chief's judgment, incapacitates the pitcher from further play. This rule was adopted effective the 2020 season.
5.4 Batting (OBR Rule 5.04)
Per OBR Rule 5.04(a), batters shall bat in the order their names appear in the batting order. Each batter's turn at bat commences when they step into the batter's box and concludes when they are put out, becomes a baserunner, or is substituted for by a pinch hitter. A batter is out if:
- Three strikes are called against them (strikeout), per Rule 5.09(a)(1).
- A fair or foul fly ball (not a foul tip) is caught by a fielder before it touches the ground, per Rule 5.09(a)(1).
- An infield fly is declared under the Infield Fly Rule (Rule 5.09(a)(12)).
- The batter hits into a force play or is tagged out.
Per OBR Rule 5.04(b)(4), the batter may leave the batter's box once per plate appearance without penalty, provided the batter does not delay the game. Violation of time limits (see pitch clock rules) results in a called strike.
5.5 Baserunning (OBR Rule 5.05–5.09)
Per OBR Rule 5.05(a), a batter becomes a baserunner when:
- A fair ball is hit that is not caught on the fly.
- The catcher fails to catch the third strike and first base is unoccupied, or there are two outs (dropped third strike, Rule 5.05(a)(2)).
- Four balls (a walk) are called by the umpire, per Rule 5.05(b)(1).
- The batter is hit by a pitched ball and attempts to avoid the pitch, per Rule 5.05(b)(2).
- A fair ball, in the umpire's judgment, is deflected by a fielder and leaves the playing field, per Rule 5.05(b)(3).
Runners must touch bases in order (first, second, third, home) and may be forced out or tagged out. A baserunner is out if they run more than 3 feet (91.44 cm) outside a direct line between bases to avoid a tag (Rule 5.09(b)(1)), unless doing so is to avoid interfering with a fielder fielding a batted ball.
5.6 The Infield Fly Rule (OBR Rule 5.09(a)(12))
Per OBR Rule 5.09(a)(12), an infield fly is a fair fly ball (not a line drive or bunt) that can be caught by an infielder with ordinary effort, when first and second bases, or first, second, and third bases are occupied before two are out. The batter is declared out by the umpire immediately; runners may advance at their own risk after the ball is caught or they may remain on their bases.
5.7 Shift Restrictions (OBR Rule 5.02(c)) — Effective 2023
Per OBR Rule 5.02(c), beginning in 2023, infield positioning restrictions require that at the time of each pitch, all four infielders must be positioned within the outer boundary of the infield (i.e., on the infield dirt or grass of the infield area), with two infielders on each side of second base. No infielder may position themselves in the outfield grass prior to the pitch. Violation results in the offensive team's manager choosing to accept the result of the play or having an automatic ball added to the count.
5.8 Recording Outs (OBR Rule 5.09)
Per OBR Rule 5.09, the defensive team records outs in the following ways (among others):
- A fly ball caught before touching the ground (out on appeal or force not required).
- A runner tagged with the ball while not in contact with a base (tag out).
- A runner is forced to advance and the fielder with the ball touches the base before the runner (force out).
- A batter-runner is tagged or the ball beats the runner to first base.
- A runner passes another runner who has not been put out (Rule 5.09(b)(9)).
- A runner fails to retouch a base after a fly ball is caught and an appeal is properly made (Rule 5.09(c)).