What is Catcher Framing Runs (CAB)? Definition, Formula, and Example
Catcher Framing Runs (CAB) is an advanced metric that quantifies the number of runs a catcher saves or costs their team by getting called strikes on pitches outside the strike zone.
What is Catcher Framing Runs (CAB)?
Catcher Framing Runs (CAB) is a Statcast metric that quantifies the total number of runs a catcher saves or costs their team through pitch framing. Also referred to as Catcher Framing Runs Above Average, it measures how effectively a backstop receives pitches in the shadow of the strike zone—specifically the areas just off the plate where a borderline pitch could be called either a ball or a strike. By turning balls into called strikes, a framer directly increases the odds of recording an out without giving the batter a free pass.
How Catcher Framing Runs is Calculated
CAB relies on the probability of a pitch being called a strike based on its exact location, pitch type, velocity, and movement. Because home-plate umpires rely on human judgment, the strike zone is not a perfect rectangle. Catchers exploit this by subtly shifting their mitts to make borderline pitches look like strikes.
The calculation uses Run Expectancy (RE) based on the count. A called strike on a 1-1 pitch dramatically shifts the odds in the pitcher's favor compared to a called ball (which results in a 2-1 count). Statcast calculates CAB by evaluating every pitch a catcher receives near the zone:
1. Determine the league-average probability of a pitch in that specific location being called a strike.
2. If the catcher gets a called strike where the league average predicts only a 20% chance of a strike, the catcher gets credit for the remaining 80%.
3. Multiply that difference by the specific Run Expectancy value of the count change.
4. Sum these values over the course of a season.
A score of zero means the catcher generated exactly the number of called strikes expected of an average receiver. Positive numbers are above average; negative numbers are below average.
Worked Example
In 2023, Patrick Bailey of the San Francisco Giants led MLB with 16 Catcher Framing Runs. This means that through his receiving mechanics alone, Bailey prevented 16 runs from scoring over the course of the season compared to an average catcher. Conversely, during the same season, several veteran catchers posted negative CAB scores in the -10 to -15 range, actively costing their pitching staffs runs by failing to secure borderline calls. A catcher with a +16 CAB provides immense hidden value; in the context of WAR, 10 runs roughly equals one win, meaning Bailey's glove was worth over a win and a half above a replacement-level framer.
Why Catcher Framing Runs Matters
CAB drives high-stakes roster decisions across MLB front offices. Teams pay premiums for elite framers because the metric directly correlates with run prevention. Pitchers with high walk rates or those who nibble the edges of the zone benefit massively from a high-CAB catcher. For fantasy baseball and DFS players, a catcher with a high CAB can subtly lower a pitcher's ERA and WHIP, making battery matchups a crucial consideration when setting daily lineups. Evaluating catchers solely on their pop time and caught-stealing rates misses the largest defensive contribution they make to a game.
Limitations and Common Misconceptions
CAB is strictly a receiving metric; it does not evaluate a catcher's ability to block balls in the dirt, control the running game, or call a game. A common misconception is that catchers with high CAB are "cheating" by pulling pitches into the zone. While some historical framers did pull pitches, modern metrics and the automated ABS challenge system have heavily penalized glove manipulation. Today's elite CAB scores come from "quiet" receiving—absorbing the pitch with stiff wrists so the mitt does not drift out of the zone. Furthermore, CAB is subject to regression; aging catchers frequently see sharp declines in their framing scores as their reflexes and flexibility wane.
Related Terms
In Legends Deck: Catcher Framing Runs directly influences the defensive ratings on Legends Deck catcher cards. A backstop with a high CAB will boost the overall effectiveness of your pitching staff in-game, widening the simulated strike zone and suppressing opposing on-base percentages.