Glossary

Every number on this site reads the same way: 100 is league average, higher is better, and each point is one percent of league runs. That means the indexes add up. A great bat and a great glove stack into one number instead of living on separate pages.

Our indexes

NEXT+

The headline number: everything a player does, as one rate. Hitting, fielding, position, and pitching for the rare player who does both. 100 is average; 120 means twenty percent more valuable than the average player, per opportunity.

HIT+

Run creation at the plate, adjusted for park and league. 100 is an average hitter. Works like wRC+.

PITCH+

Run prevention on the mound, on the same scale. A 120 pitcher and a 120 hitter are equally far above average.

FIELD+

Defense at a position, on the same scale. 100 is the average fielder at that position, so a 110 shortstop and a 110 left fielder are each ten percent better than their own peers.

Value stats

nWAR and pWAR

Wins above replacement, for position players and pitchers. How many wins a player added compared to a freely available fill-in, combining all his ledgers.

Bat runs

Runs above or below the average hitter, with the bat alone.

Def runs

Runs saved or cost in the field, including the value of playing a harder position. Real runs, not index points.

Runs saved

For pitchers and fielders: runs prevented compared to an average player given the same workload.

Rate stats

AVG / OBP / SLG

The classic slash line: batting average, on-base percentage, and slugging percentage. OPS is the last two added together.

wOBA

On-base percentage's smarter cousin: every way of reaching base is weighted by how many runs it is actually worth.

K% and BB%

Strikeouts and walks as a share of plate appearances (for hitters) or batters faced (for pitchers).

Whiff%

Swings that miss, as a share of all swings.

Chase%

Swings at pitches outside the strike zone, as a share of pitches outside the zone.

Counting stats

PA and BF

Plate appearances for hitters, batters faced for pitchers. The denominators for everything.

G, AB, R, H, 2B, 3B, HR, RBI, BB, SO, SB

Games, at bats, runs, hits, doubles, triples, home runs, runs batted in, walks, strikeouts, stolen bases. The box score.

Chances

Batted balls a fielder was responsible for. The fielding denominator.

Statcast

Exit velocity

How hard the ball leaves the bat, in miles per hour. Average is around 89.

Launch angle

The vertical angle the ball leaves the bat. Line drives live in the low teens.

Barrel%

The share of batted balls hit with the near-ideal combination of speed and angle. Barrels become extra-base hits more often than anything else.

Hard-hit%

The share of batted balls at 95 mph or harder.

Sweet-spot%

The share of batted balls launched between 8 and 32 degrees.

xBA, xSLG, xwOBA

Expected stats: what a player's line would look like if every batted ball got the league-average result for its speed and angle. Good for spotting luck.

Sprint speed

Feet per second at full effort. 27 is about average; 30 is elite.

Framing

Runs a catcher adds by getting borderline pitches called strikes.

Reading the projections

Projections here are built the same way the season-to-date numbers are measured, and every projected column says which season it is for. A projection is an estimate of true talent, so it will always look tamer than a hot streak. That is the point.