A balk in baseball is an illegal motion by a pitcher with runners on base. There are 13 official balk rules in the MLB rulebook (Rule 6.02a), and any one of them — caught by an umpire — automatically advances every runner one base.
The most common balk is failing to come to a complete stop in the set position. The penalty is immediate and non-negotiable: runners advance, the pitch is nullified, and the count stays the same. Balks only apply with runners on base — you cannot balk from the windup with empty bases. Here’s the complete breakdown of every balk rule, what each one looks like, and how the 2023 pitch clock changed the balk landscape forever.
Balk in baseball — complete guide
All 13 official MLB balk rules, common situations, pitch clock changes, and records.
By the numbers
1898
Year rule introduced
90
Carlton career (record)
The 13 official MLB balk rules (Rule 6.02a)
Every way a pitcher can be called for a balk in Major League Baseball — only applies with runners on base
#
Rule
What it looks like
1
Starts pitching motion, doesn’t deliver
Pitcher begins any natural pitching motion and stops mid-delivery. Most common type of balk.
2
Fakes throw to 1st or 3rd base
Pitcher must throw if engaged in pickoff motion. No fake throws to 1st or 3rd (rule updated 2013).
3
Doesn’t step toward the base before throwing
When throwing to a base from the rubber, lead foot must step directly toward that base.
4
Throws or fakes throw to unoccupied base
Cannot throw/fake to a base with no runner unless making a legitimate play.
5
Makes an illegal pitch (quick pitch)
Quick-pitching before batter is set, or delivering from off the rubber.
6
Pitches while not facing the batter
Extremely rare. Body must be oriented toward home plate during delivery.
7
Pitches without being on the rubber
Must have foot in contact with rubber when engaging in pitching motion.
8
Unnecessarily delays the game
Gray area, now largely covered by 2023 pitch clock rules.
9
Stands on rubber without the ball
“Hidden ball” defense — pitcher cannot be on the rubber while another player has the ball.
10
Removes hand from ball after coming set
Once set, hand must stay together until delivery, pickoff, or step-off.
11
Drops the ball while on the rubber
Accidental or intentional — if the ball drops while engaged, it’s a balk.
12
IBB pitch with catcher outside catcher’s box
Largely moot since 2017 (intentional walks now signaled without pitches).
13
Delivers from set without coming to stop
The most common modern balk. Pitcher must come to a defined complete stop in the set position.
How the 2023 pitch clock changed balks
The new disengagement rules added a layer on top of the existing 13 balk rules
Rule
Limit
Penalty if violated
Pitch clock (bases empty)
15 sec
Automatic ball. Not a balk (no runners to advance).
Pitch clock (runners on)
18 sec
Automatic ball. Reduced from 20s in 2024.
Disengagements per PA
2 max
3rd step-off or pickoff = balk (unless runner picked off).
Batter in batter’s box
8 sec
Batter ready by 8s on clock or automatic strike.
Step-off resets
After runner advances
Count resets to zero if a runner steals or advances.
All-time MLB balk records
Career and single-season balk leaders in MLB history
Pitcher
Balks
Years / season
Notes
Steve Carlton
90
Career
All-time record. Also 144 career pickoffs (record).
Steve Carlton
11
1979
Single-season modern record. Phillies year.
Dave Stewart
16
1988
Inflated by 1988 “balk year” — MLB cracked down on rule #13.
1988 MLB Season
924
League total
“Year of the Balk.” 3.6× more than any other season.
Bob Welch
3
One inning
Most in single inning (1988 vs Yankees).
Steve Carlton pickoffs
144
Career
Same lefty deception that produced 90 balks.
The takeaway
A balk is an illegal pitcher motion with runners on base. There are 13 official balk rules in the MLB rulebook (Rule 6.02a), all designed to prevent pitchers from deceiving baserunners. The penalty is automatic: every runner advances one base, the pitch is nullified, and the count stays the same. The most common balk is failing to come to a complete stop in the set position (Rule #13). The 2023 pitch clock added the “disengagement balk” — pitchers can step off the rubber or attempt pickoffs only twice per plate appearance. Steve Carlton holds the all-time career balks record at 90, and 1988 was MLB’s “Year of the Balk” when umpires cracked down on rule #13 enforcement.
Sources: MLB Official Baseball Rules, Baseball-Reference, MLB.com 2023 pitch clock documentation. Verified May 2026.
Why the rule exists
The balk rule exists to prevent pitchers from deceiving baserunners. Without it, pitchers could fake throws, hesitate mid-delivery, and trick runners into committing to a stolen base attempt before the pitcher actually committed to anything.
The rule was introduced in 1898 — making it one of the oldest rules still in the modern rulebook. The core principle from the official MLB rulebook: “the purpose of the balk rule is to prevent the pitcher from deliberately deceiving the base runner.” Every one of the 13 specific balk situations traces back to that single intent. Once the pitcher engages the rubber with a runner on base, the pitcher has committed to a delivery or pickoff — they can’t change their mind without consequence.
How the pitch clock changed everything (2023+)
The 2023 pitch clock didn’t replace the balk rule — it stacked on top of it. Pitchers now have 15 seconds with bases empty and 18 seconds with runners on to begin their delivery. They can also “disengage” the rubber (step-off or pickoff attempt) a maximum of two times per plate appearance.
A third disengagement is automatic — if the runner isn’t picked off, a balk is called. This new “disengagement balk” added a tactical wrinkle: runners now know after the second pickoff attempt that the pitcher cannot throw over again without risking a balk, which has fueled the modern stolen base resurgence. In 2025, MLB recorded the highest stolen base success rate in 70+ years, partly because of this exact rule change.
Steve Carlton and the all-time balk records
Steve Carlton holds the all-time MLB record with 90 career balks across his Hall of Fame career (1965-1988). He also holds the single-season record with 11 balks in 1979. The reason isn’t carelessness — it’s that Carlton had one of the most deceptive pickoff moves in MLB history (his 144 career pickoffs are also a record), and umpires aggressively called him for toeing the line. The connection between pickoff success and balk calls is direct: pitchers who try to deceive runners get more pickoffs AND more balks. The 2013 rule change that eliminated fake throws to third base was largely in response to pitchers like Carlton finding gray areas — modern pitchers can no longer fake to third and pivot to first.
How to spot a balk live
The easiest balks to spot are the failure-to-stop balks (Rule #13) — pitchers must come to a clear, defined stop in the set position before delivering. If you see the pitcher’s hands moving continuously from glove-set to delivery without pausing, that’s a balk. The second-easiest to spot are flinch balks (Rule #1) — any natural pitching motion that doesn’t result in delivery is a balk. The hardest to catch are the foot-position balks (Rules #3 and #4) involving step direction and unoccupied bases, which often happen too fast for casual viewers. Watch the umpire’s signal — a balk call comes with both arms extended pointing to the runners, then a verbal “that’s a balk” call. Once the umpire calls it, runners advance immediately and the play is dead.
— Drew, Legion Report
