Under Rule 5.10(g)(1) of the 2026 Official Baseball Rules (PDF pages 67–68), the starting pitcher or any substitute pitcher must pitch to a minimum of three consecutive batters—until each batter is put out or reaches first base—or until the offensive team is put out, unless the substitute pitcher sustains an injury or illness that, in the Umpire-in-Chief’s judgment, incapacitates him from further play as a pitcher. Rule 5.10(g)(2) further mandates that any pitcher who warms up on the field prior to the start of an inning must pitch to at least the first batter of that inning absent an incapacitating injury.
Intentional Walks, Pickoffs, and the Multi-Inning Carryover Matrix
The Official Baseball Rules Comment to Rule 5.10(g)(1) clarifies how non-batted plate appearances and inning endings interact with the three-batter mandate. An intentional base on balls counts toward the three-batter requirement, whereas picking off a runner does not count as a batter faced—though a pickoff that records the third out of the half-inning satisfies the rule and allows the pitcher to be removed between innings. However, if a relief pitcher records the final out of an inning before facing three batters and returns to pitch the subsequent inning, he must complete pitching to as many consecutive batters in the second inning as are needed to reach three total batters across the two frames (facing two batters in the second inning after facing one in the first, or one batter in the second inning after facing two in the first).
Enforcement Principles and the Ejection-Walk Sanction
Three explicit enforcement principles govern edge cases under Rule 5.10(g)(1): Principle 1 credits the pitcher on the mound at the completion of a plate appearance with facing that batter when a mid-plate-appearance injury change occurs; Principle 2 bars a pitcher from switching to another defensive position until he has satisfied the three-batter minimum or a new inning (other than the first) begins; and Principle 3 establishes progressive sanctions for improper removal attempts—charging a mound visit on an initial premature signal, warning the manager on a second premature attempt in the same inning, and ejecting both the pitcher and manager while awarding no-pitch intentional walks to the number of batters required to complete the ejected pitcher’s three-batter minimum if a club blatantly removes its pitcher from the field early.