Stats Glossary

Plain-English explanations for every stat, with quality tiers and Hall of Fame context.

Tier Legend

🏆 Hall of Fame
🔥 Elite
Great
Above Avg
Average
⬇️ Below Avg

Batting

(10 stats)

Batting Average

AVG
Batting

Hits divided by at-bats. The most basic measure of how often a player gets a hit. .300 is the gold standard.

.300+ is excellent; below .230 is a concern

Hall of Fame.330
Elite.300
Great.280
Above Avg.260
Average.240
Below Avg< .240
🏆 HoF ref: Tony Gwynn (.338 career)

On-Base Percentage

OBP
Batting

How often a player reaches base (hits, walks, HBP) per plate appearance. The most important on-base stat.

.370+ is elite; below .300 is a liability

Hall of Fame.400
Elite.370
Great.350
Above Avg.330
Average.310
Below Avg< .310
🏆 HoF ref: Barry Bonds (.609 single-season record)

Slugging Percentage

SLG
Batting

Total bases divided by at-bats — rewards extra-base hits. A home run counts 4x more than a single.

.530+ is elite; below .380 is weak

Hall of Fame.600
Elite.530
Great.480
Above Avg.430
Average.390
Below Avg< .390
🏆 HoF ref: Babe Ruth (.690 career)

OPS

OPS
Batting

OBP + SLG. Quick all-in-one hitting measure. 1.000+ is historically elite.

.900+ is elite; below .700 is below average

Hall of Fame1.000
Elite.900
Great.825
Above Avg.750
Average.700
Below Avg< .700
🏆 HoF ref: Babe Ruth (1.164 career)

Home Runs

HR
Batting

Home runs in a season. 40+ puts you among the league leaders. 60+ is legendary.

35+ is elite power; 10 is average for a position player

Hall of Fame45
Elite35
Great25
Above Avg18
Average10
Below Avg< 10
🏆 HoF ref: Barry Bonds (73 in 2001)

RBI

RBI
Batting

Runs batted in. Partly dependent on teammates reaching base, but still a classic power measure.

100+ is excellent; 120+ puts you in MVP conversation

Hall of Fame120
Elite100
Great85
Above Avg70
Average55
Below Avg< 55
🏆 HoF ref: Hack Wilson (191 in 1930)

Hits

H
Batting

Total hits. 200 hits in a season is the benchmark for elite contact hitters.

200 hits is a gold-standard season; below 130 is below average

Hall of Fame200
Elite185
Great170
Above Avg155
Average130
Below Avg< 130
🏆 HoF ref: Ichiro Suzuki (262 in 2004)

Stolen Bases

SB
Batting

Stolen bases. Measures baserunning aggression. 30+ in a season is excellent speed.

40+ is elite; below 6 is below average for speedsters

Hall of Fame40
Elite30
Great20
Above Avg12
Average6
Below Avg< 6
🏆 HoF ref: Rickey Henderson (130 in 1982)

Walk Rate

BB%
Batting

Walks per plate appearance. Shows plate discipline — a batter who draws walks gives their team more baserunners.

11%+ is elite plate discipline; below 5% is poor

Hall of Fame14%
Elite11%
Great9%
Above Avg7%
Average5%
Below Avg< 5%
🏆 HoF ref: Barry Bonds (20.3% career)

Strikeout Rate

K%
Batting

Strikeouts per plate appearance. The main downside of an aggressive or overpowered hitter. Lower is better for position players.

Below 12% is excellent contact; above 27% is problematic

Hall of Fame12%
Elite15%
Great18%
Above Avg22%
Average27%
Below Avg> 27%
🏆 HoF ref: Tony Gwynn (< 5% career K%)

Pitching

(5 stats)

ERA

ERA
Pitching

Earned runs allowed per 9 innings. The flagship pitching stat. Lower is better — under 3.00 is elite.

Under 2.75 is elite; above 4.50 is below average

Hall of Fame2.00
Elite2.75
Great3.25
Above Avg3.75
Average4.50
Below Avg> 4.50
🏆 HoF ref: Walter Johnson (1.14 career ERA)

WHIP

WHIP
Pitching

Walks + Hits per inning pitched. Measures how many baserunners a pitcher allows. Under 1.10 is excellent.

Under 1.00 is elite; above 1.35 is below average

Hall of Fame0.85
Elite1.00
Great1.10
Above Avg1.20
Average1.35
Below Avg> 1.35
🏆 HoF ref: Pedro Martinez (0.737 single-season record)

K/9

K/9
Pitching

Strikeouts per 9 innings. Higher means the pitcher dominates hitters. 10+ is elite.

10.5+ is elite; below 7.5 is below average

Hall of Fame12.00
Elite10.50
Great9.50
Above Avg8.50
Average7.50
Below Avg< 7.50
🏆 HoF ref: Randy Johnson (10.6 career K/9)

BB/9

BB/9
Pitching

Walks per 9 innings. Lower means better control. Under 2.0 is excellent command.

Under 1.5 is elite control; above 3.5 is poor command

Hall of Fame1.50
Elite2.00
Great2.50
Above Avg3.00
Average3.50
Below Avg> 3.50
🏆 HoF ref: Curt Schilling (1.06 career BB/9 among starters)

K% (Pitching)

K%
Pitching

Percentage of batters faced who strike out. A cleaner version of K/9 that doesn't depend on league run environment.

32%+ is elite; below 15% means hitters put the ball in play often

Hall of Fame32%
Elite27%
Great23%
Above Avg19%
Average15%
Below Avg< 15%
🏆 HoF ref: Jacob deGrom (37.2% in 2018)

Statcast & Advanced

(4 stats)

Barrel Rate

Brl%
Statcast & Advanced

% of batted balls that are 'barreled' — the optimal combination of exit speed and launch angle for a hit or HR.

15%+ is elite; below 4% means rarely making ideal contact

Hall of Fame20%
Elite15%
Great10%
Above Avg7%
Average4%
Below Avg< 4%
🏆 HoF ref: Aaron Judge (~20% barrel rate seasons)

Hard Hit %

HH%
Statcast & Advanced

% of batted balls hit 95+ mph. Strong predictor of future offensive success.

45%+ is elite; below 30% indicates weak contact

Hall of Fame50%
Elite45%
Great40%
Above Avg35%
Average30%
Below Avg< 30%
🏆 HoF ref: Giancarlo Stanton (consistently 50%+)

Avg Exit Velocity

AvgEV
Statcast & Advanced

Average speed of batted balls in mph. Higher means harder contact on average.

92+ mph is elite; below 85 mph is soft contact

Hall of Fame95 mph
Elite92 mph
Great90 mph
Above Avg88 mph
Average85 mph
Below Avg< 85 mph
🏆 HoF ref: Aaron Judge (consistently 95+ mph)

Sprint Speed

Spd
Statcast & Advanced

Average running speed in feet/second on competitive plays (home-to-first, extra bases, etc.).

28.5+ ft/s is elite; below 25 ft/s is well below average

Hall of Fame30 ft/s
Elite28.5 ft/s
Great27.5 ft/s
Above Avg26.5 ft/s
Average25 ft/s
Below Avg< 25 ft/s
🏆 HoF ref: Trea Turner (consistently 30+ ft/s)

Thresholds are single-season benchmarks for MLB position players and starting pitchers. Context matters — park factors, era, and role all affect evaluation.