Check swings
Famous loophole: the rulebook never defines a swing. Whether the batter 'struck at' the ball is pure umpire judgment, appealable to the base umpire — first base umpire for right-handed hitters, third base for lefties — and never reviewable by replay.
- No definition exists: 'did he go' has no written standard about wrists breaking or the bat crossing the plate.
- If the pitch is called a ball, the defense (usually the catcher) can ask for the appeal; on a called strike, the call is already made.
- The base umpire's answer is final — no replay, no further appeal.
- A pitch that hits the batter mid-check-swing is a dead-ball strike, not a hit by pitch, if the appeal says he swung.
Full count, two outs, runner going — pitch called ball four, catcher points to first, and the base umpire rings him up.
Ruling · Strike three, inning over. The appeal turned the walk into a strikeout, and nothing about it is reviewable.
Flips walks into strikeouts (and vice versa) on the least defined judgment in the rulebook — outcomes swing entirely on which umpire is asked.
Reference note: one or more section citations on this page are being verified against the current official rulebook edition. The explanation reflects the rule as played; confirm the exact subsection in the official text.