MLB / Professional Rules
The full professional game. Watching MLB with your kid is more fun when you both understand what’s happening.
The basics
| Rule | Details |
|---|
| Game length | 9 innings (extra innings if tied) |
| Field | 90-foot basepaths, 60’6″ pitching distance |
| Bats | Wood only (maple, ash, birch) |
| DH | Universal DH in both AL and NL (since 2022) |
| Rosters | 26 players active, 40-man expanded roster |
Recent rule changes
| Rule | Year | What It Does |
|---|
| Pitch clock | 2023 | Pitcher has 15 sec (empty bases) or 20 sec (runners on) between pitches |
| Bigger bases | 2023 | Bases increased from 15″ to 18″ square (more stolen bases, fewer collisions) |
| Shift ban | 2023 | Infielders must have two players on each side of second base when the pitch is thrown |
| Universal DH | 2022 | Pitcher never bats — DH in both leagues |
| Ghost runner | 2020+ | Extra innings start with a runner on second base |
What makes MLB different
| Aspect | Details |
|---|
| Umpire judgment | Balls, strikes, and check swings are human calls (with replay for other plays) |
| Challenge system | Each manager gets one challenge per game. Additional if the first is successful. |
| Mound visits | Limited to 5 per team per 9-inning game |
| Batter’s box rule | Batter must keep one foot in the box between pitches |
Watch games together. Understanding the rules makes watching MLB way more fun. See our
classic games page for the best games to start with.
