What is a balk in baseball?
I · Intermediate · Pitching and game management · 6 of 9A balk is an illegal act by the pitcher with at least one runner on base. Every runner advances one base. Most balks are ways of deceiving a runner: starting to pitch and stopping, faking a throw to first, throwing to a base without stepping towards it or pitching from the set without a full stop.
How it works
- The definition: "an illegal act by the pitcher with a runner(s) on base. All runners advance one base."
- Starting and stopping: making any motion of the delivery and not completing the pitch.
- Faking to first or third: a feint from the rubber without completing the throw.
- No step: throwing to a base without first stepping directly towards it.
- An empty base: throwing or feinting to a base where no play on a runner is possible.
- No stop: pitching from the set without a complete and discernible stop.
- Hands apart: taking a hand off the ball after coming set, other than to pitch or throw.
- Dropping the ball: while touching the rubber.
- Off the rubber: making a pitching motion while not touching it.
- Without the ball: standing on the mound without the ball during a hidden-ball trick.
- Second base is different: stepping towards second without throwing is legal if a runner is there.
- The play may stand: if the batter and all runners advance at least one base anyway, the balk is ignored.
The glossary has the balk, the set position, the pickoff, the stolen base, the pivot foot and the pitcher.
Tricky cases
The pitcher, on the rubber, fakes a throw to first and holds the ball. Balk?
Yes. A feinting motion towards first base without completing the throw is a balk.
The pitcher lifts the front leg, steps towards second base, where there is a runner, and does not throw. Balk?
No. Stepping towards second without completing the throw is legal if the base is occupied.
A balk is called, the pitch is thrown anyway and the batter hits a double that scores the runner. What stands?
The play. If the batter reaches base and all runners advance at least one base, the balk is ignored.
The batter steps out as the pitcher starts the delivery, and the pitcher stops. Balk?
No. Both have broken a rule, so the umpire calls "Time" and the play starts again.
Why the rule exists
A runner taking a lead off the base is gambling on reading the pitcher. The balk rules set the limits of honest deception: a pitcher may try to catch a runner, but not by pretending to pitch. Without them, stealing a base would be close to impossible.
Where it differs
| Where | What changes | Source |
|---|---|---|
| Runners on base | The illegal act is a balk; runners advance | WBSC Baseball Rule 13.10 |
| Bases empty | The same act is an illegal pitch; a ball is called | WBSC Baseball Rule 13.6.1 |
| Catcher out of the box at the pitch | Balk | WBSC Baseball Rule 7.5.1; 13.10.15 |
| Catcher interferes on a squeeze or steal of home | Balk, and the batter gets first base | WBSC Baseball Rule 12.6 |
From the rule book
World Baseball Softball Confederation, Official Rules of Baseball (2025-2026 edition), Rules 6.2, 12.6, 13.6 and 13.10. Checked 14 October 2026. Official document: WBSC Official Rules of Baseball 2025-2026 (PDF).