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MLB Advanced Statistics + Acronym Definitions:

Understand key MLB advanced stats and acronyms like wOBA, xFIP, BABIP and more to level up your baseball research and betting insights.

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Written by Jalen Reynolds
Updated this week

BABIP - ‘Batting Average on Balls in Play’ this excludes strikeouts + Homeruns(out of the park only)

wOBA - ‘Weighted On Base Average’ measures a hitter's overall offensive value per plate appearance, considering the impact of different offensive outcomes on run scoring. It goes beyond traditional stats like on-base percentage and slugging percentage by assigning weights to various events like singles, doubles, home runs, and walks, reflecting their actual run value.

Hard Hit % - Statcast defines a 'hard-hit ball' as one hit with an exit velocity of 95 mph or higher, and a player's "hard-hit rate" is simply showing the percentage of batted balls that were hit at 95 mph or more.

BAA - opponents' batting average" or "batting average against," is determined by dividing the number of hits against a given pitcher by the number of at-bats against him. BAA is very common in evaluating pitchers -- especially when assessing opponent handed-ness splits.

BB/K: Walk-to-Strikeout Ratio

It shows how often a team (or player) walks compared to how often they strike out:

A higher BB/K means more walks per strikeout (shows better plate discipline).

A lower BB/K (like 0.4) means they strike out a lot compared to how often they walk — not ideal for offensive efficiency.

Weighted Runs Created + : wRC+ takes the statistic Runs Created and adjusts that number to account for important external factors -- like ballpark or era. It's adjusted, so a wRC+ of 100 is league average and 150 would be 50 percent above league average.

For example, a player who plays his home games at hitter-friendly Coors Field will have a lower wRC+ than a player who posts identical stats at pitcher-friendly Oakland Coliseum.

WHIP (Walks + Hits per Inning Pitched) Measures how many baserunners a pitcher allows per inning. Calculated by adding walks and hits allowed, then dividing by innings pitched. A lower WHIP indicates better control and fewer runners allowed.

FIP - FIP is similar to ERA, but it focuses solely on the events a pitcher has the most control over -- strikeouts, walks, hit-by-pitches and home runs. It entirely removes results on balls hit into the field of play.

For example: If a pitcher has surrendered a high average on balls in play, his FIP will likely be lower than his ERA. Balls in play are not part of the FIP equation because a pitcher is believed to have limited control over their outcome.

BF - ‘BF’ is the abbreviation for ‘Batters Faced’. This is the total count of hitters that the pitcher has faced in the sample size tied to the stat.

PC - ‘PC’ is the abbreviation for ‘Pitch Count’. This measures the amount of pitches a batter has seen or the amount of pitches thrown by a pitcher, depending on what player this statistic is tied to.

PA - A plate appearance refers to a batter's turn at the plate. Each completed turn batting is one plate appearance. Plate appearances can often be confused with at-bats. But unlike with at-bats -- which only occur on certain results -- a plate appearance takes into account every single time a batter comes up and a result between batter and pitcher is obtained.

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