What are Balks?
Balks are called by an umpire. Mostly, they are called because of actions that might deceive the batter and baserunners. Also, balks can be called for specific actions that are against rules intended to
support fair play and safety. Although there are many rules regarding balks, umpire judgement is important.
Baseball legend is that in the 1961 All-Star game, high wind gusts caused pitcher Stu Miller to sway and he was called for a balk. Perhaps extreme weather can cause a balk call!
When an umpire calls a balk, the ball is instantly dead and any baserunners advance one base. Balks must be tracked as part of each game’s record per the rules of baseball.
Nevertheless, balks are rare. In the 2025 regular season, there was an average of 0.24 balks per game played (about one in every four games played). In 2025, only 10 pitchers had more than two balks. One of those ten was former Diamondback relief pitcher (now free agent) José Castillo, who had 3.
Balk Rules.
Section 6.02(a) Section 6.02(a) of the official baseball rules lists 13 balk rules. Most of them focus on footwork (for example pitcher must step in direction of throw before throwing), and the pitcher must not pretend to throw, and the pitcher must ensure the batter is ready before throwing.
An interesting rule is 6.02(a)(8) that the pitcher must not unnecessarily delay the game. It is interesting because it aligns with recent changes to increase the pace of play.
A significant rule is 6.02(a)(13). It requires that when a pitcher delivers from a set position, he must pause before throwing.
The 13 balk rules in section 6.02(a) and (b) are supplemented by other sections of the rules.
Non-Pitchers can cause a balk.
Section 5.02. The catcher must be positioned with both feet within in the catcher’s box. The penalty is a balk. When the catcher is in the one knee stance, this rule becomes interesting! Can the catcher’s knee be outside the catcher’s box?
6.01(g) When a runner on third base is attempting to score, if any fielder, without the ball, steps in front of home plate or touches the batter, then “…the pitcher shall be charged with a balk…” Theoretically, any player on the field can cause the pitcher to be charged for a balk!
6.02(d)(4) If a play immediately follows the umpire calling out a pitcher for applying a foreign substance to the baseball, the manager of the at-bat team can choose whether to accept the play or alternatively have the umpire call a balk. Incredibly, the manager of the other team can cause a balk to be called!
More Ways a Pitcher can cause a balk. 5.07(a) and (d) adds more details about the required pitcher footwork, and requirements for the windup position and set position. Most interesting is rule 5.07(a) that the pitcher can’t disengage after receiving the sign.
Balk rules can change. Prior to the 2023 season, a new rule was added. It limited pitchers to two disengagements per plate appearance. The third disengagement is a balk, unless it is a successful pickoff attempt.
Balks and Stolen Bases.
Pitcher deception is a two-edged sword. It can improve a pitcher’s performance against batters and it can improve their effectiveness of pickoff moves. The umpire limits that deception by calling balks when the pitcher’s deception goes beyond what the rules allow.
As you can easily imagine, some pitchers like to test the limits. Those pitchers get called for more balks than other pitchers. Depending on your viewpoint, being called for a balk can be a considered part of being the best pitcher possible. Great pickoff moves, in addition to resulting in balks, can result in runners being called out and runners being less aggressive in stealing bases.
Let’s look at 2025 Diamondbacks starting pitchers Corbin Burnes and Merrill Kelly. In 2025, with two balks each they have more balks than the other starters. They always have more balks than average; it’s normal for them. In the two prior seasons, Burnes averaged 2 balks per season and Kelly averaged 3 balks per season.
Their balks are part of being great pitchers. For Kelly, his pickoffs are awesome. In 2025, his statistic of 5 pickoffs minus errors-in-pickoff-attempts is very much better than any Diamondbacks pitcher. For Burnes, in 2025 he reduced his stolen bases. His statistic of 0.8 stolen-bases-per-batter-faced is better than all Diamondbacks pitchers except Ryne Nelson.
The following table shows, for all 2025 Diamondbacks starting pitchers, two statistics: pickoffs minus errors-in-pickoff-attempts and stolen-bases-per-batter-faced. Mena and Diaz were added to the table because they might be starters next season. Data from Baseball Savant.
Diamondbacks Relievers.
Only two Diamondbacks relievers were charged with a balk (Jose Castillo (3), and Ryan Thompson (1)).
Two other Diamondbacks relievers have low pickoff-attempts-per-stolen-base. Perhaps more pickoff attempts would reduce their stolen bases. Details follow:
- Andrew Saalfrank, 5 stolen bases, 2 pickoff attempts, 0 pickoffs.
- AJ Puk, 3 stolen bases, 1 pickoff attempt, 0 pickoffs.
On the other hand, it is unclear that increased pickoff moves will reduce stolen bases. For example, reliever Tayler Scott’s 10 pickoff attempts (zero successful) did not prevent 12 stolen bases.
Summary.
Balks are called by an umpire. Mostly, they are called because of actions that might deceive the batter and baserunners, and for actions that are against rules intended to support fair play and safety.
When an umpire calls a balk, the ball is instantly dead and any baserunners advance one base. Balks must be tracked as part of each game’s record per the rules of baseball.
Balks are rare, about one per four games.
There are many balk rules. Non-pitchers can cause a balk to be called against the pitcher.
Pitcher deception can improve a pitcher’s performance against batters and it can improve their effectiveness of pickoff moves. Umpires limits that deception by calling balks when the pitcher’s deception goes beyond what the rules allow.
Corbin Burnes and Merrill Kelly have more balks than average. Balks may be the cost of Kelly’s great pickoff move and Burnes’ recent improved effectiveness is preventing stolen bases.
Andrew Saalfrank and AJ Puk have low pickoff attempts per stolen bases. Perhaps with an effective pickoff move they could reduce stolen bases.
