Stat Glossary
Batting
| G | Games | Games in which the player appeared. |
| PA | Plate Appearances | Trips to the plate — the denominator for most modern rate stats. Includes walks, sacrifices, and times hit by pitch, unlike at-bats. ~600–700 for a full-season regular |
| AB | At Bats | Plate appearances excluding walks, hit-by-pitches, sacrifices, and catcher's interference. |
| R | Runs | Runs scored. 100+ is an excellent season |
| H | Hits | Total hits. 200 hits is a historically notable season |
| 2B | Doubles | Two-base hits. 40+ leads most seasons |
| 3B | Triples | Three-base hits — mostly a speed stat. 10+ leads the league most years |
| HR | Home Runs | Home runs. 30+ is a power season; 40+ is elite |
| RBI | Runs Batted In | Runs driven in. Heavily dependent on teammates reaching base ahead of the batter — descriptive, not predictive. 100+ traditionally notable |
| SB | Stolen Bases | Stolen bases. 30+ marks an elite runner |
| CS | Caught Stealing | Times thrown out attempting to steal. Break-even success rate is roughly 75% — below that, running costs runs. |
| SB% | Stolen Base Percentage | Stolen-base success rate. Below the ~75% break-even, attempting steals costs the team runs. SB ÷ (SB + CS) 75% break-even; 85%+ elite |
| BB | Walks | Bases on balls. |
| IBB | Intentional Walks | Intentional walks — largely a measure of how much the opponent fears the hitter. |
| SO | Strikeouts | Times struck out. |
| HBP | Hit By Pitch | Times hit by a pitch — reaches base, counts toward OBP. |
| SF | Sacrifice Flies | Fly outs that scored a runner. Not charged as an at-bat. |
| SH | Sacrifice Bunts | Sacrifice bunts. |
| GDP | Grounded Into Double Play | Double plays grounded into. |
| TB | Total Bases | Bases gained on hits — one per single, four per homer. The numerator of slugging percentage. 1B + 2×2B + 3×3B + 4×HR 400+ is a historic season |
| XBH | Extra-Base Hits | Doubles, triples, and home runs combined. 2B + 3B + HR 70+ is an elite power season |
| LOB | Left On Base | Runners left on base over the batter's plate appearances. Heavily dependent on how often teammates are on ahead of him. |
| Pit | Pitches Seen | Total pitches seen. Grinding out long plate appearances wears down starters and feeds the walk rate. |
| P/PA | Pitches per Plate Appearance | How deep the batter works the count on average. Pitches ÷ PA league avg ~3.9; 4.2+ marks a grinder |
| GO | Ground Outs | Outs made on ground balls. |
| AO | Air Outs | Outs made on balls in the air (fly outs, line outs, pop outs). |
| GO/AO | Ground Out to Air Out Ratio | Ground outs per air out — a batted-ball profile, not a skill grade. Lower ratios (more balls in the air) tend to travel with power. GO ÷ AO league avg ~1.1 |
| AB/HR | At Bats per Home Run | How many at-bats between home runs — a classic power gauge where lower is better. AB ÷ HR under 15 is elite power |
| BB% | Walk Rate | Walks per plate appearance. A plate-discipline skill that stabilizes quickly and translates across levels. BB ÷ PA league avg ~8.5%; 12%+ excellent; <5% poor |
| K% | Strikeout Rate | Strikeouts per plate appearance. Lower is better for hitters. SO ÷ PA league avg ~22%; <15% elite contact; >30% concerning |
| AVG | Batting Average | Hits per at-bat. The classic rate stat, but it ignores walks and treats all hits equally — use OBP/SLG/wOBA for a fuller picture. H ÷ AB league avg ~.245; .300+ excellent |
| OBP | On-Base Percentage | How often the batter reaches base per plate appearance. The single most important traditional rate stat — outs are the game's scarcest resource. (H + BB + HBP) ÷ (AB + BB + HBP + SF) league avg ~.315; .380+ elite |
| SLG | Slugging Percentage | Total bases per at-bat — batting average weighted by hit type. (1B + 2×2B + 3×3B + 4×HR) ÷ AB league avg ~.400; .550+ elite |
| OPS | On-Base Plus Slugging | OBP plus SLG. A quick-and-dirty overall offense number; wOBA weighs the components more accurately. OBP + SLG league avg ~.715; .900+ elite |
| Sw | Swings | Total swings taken. |
| Whf | Swings and Misses | Swings that missed entirely. |
| Whiff% | Whiff Rate | Share of swings that miss. The purest contact-skill measure — lower means a harder bat to beat. Misses ÷ Swings league avg ~24%; under 18% elite contact |
| ISO | Isolated Power | Extra bases per at-bat — raw power stripped of singles. SLG − AVG league avg ~.155; .250+ elite power |
| BABIP | Batting Average on Balls In Play | Batting average on balls put in play (excludes HR and SO). For hitters it partly reflects speed and contact quality, but big swings from a player's career norm usually signal luck that will regress. (H − HR) ÷ (AB − SO − HR + SF) league avg ~.295 |
| wOBA | Weighted On-Base Average | OBP's smarter sibling: every way of reaching base is weighted by its actual run value (a walk is worth less than a double, which is worth less than a homer). The best single rate stat for offense. Imported, not computed here. linear-weighted value of BB, HBP, 1B, 2B, 3B, HR per PA league avg ~.320; .400+ elite |
| xwOBA | Expected wOBA | Statcast's estimate of what a hitter's wOBA *should* be, based on exit velocity, launch angle, and (for some events) sprint speed. Big gaps between wOBA and xwOBA often predict regression. compare to wOBA: higher xwOBA suggests bad luck so far |
| xBA | Expected Batting Average | Statcast's estimate of batting average from quality of contact rather than outcomes. |
| xSLG | Expected Slugging | Statcast's estimate of slugging percentage from quality of contact. |
| wRC+ | Weighted Runs Created Plus | Total offense on an index scale: 100 is exactly league average, and every point above is one percent better than average — park- and league-adjusted, so eras and ballparks compare cleanly. Imported, not computed here. 100 = average; 140+ elite; 160+ MVP-caliber |
| WAR | Wins Above Replacement | Total player value — hitting, baserunning, defense, position — expressed as wins added versus a replacement-level player. Imported from MLB's statsapi; other sites' WAR models will differ. 2+ solid starter; 4+ All-Star; 6+ MVP-caliber |
Fielding
| Pos | Position | The position this fielding line covers. A player who logs innings at several spots has a separate line for each. |
| G | Games | Games appearing at the position. |
| GS | Games Started | Games started at the position. |
| Inn | Innings | Innings played at the position. |
| PO | Putouts | Outs a fielder recorded directly — catching a fly, tagging a runner, or taking a throw at a base. Volume is very position-dependent (first basemen and catchers dominate). |
| A | Assists | Times the fielder threw or deflected the ball toward recording an out. The core range stat for infielders. |
| E | Errors | Misplays the scorer judged should have been made with ordinary effort. A noisy, subjective stat — read range factor alongside it. |
| DP | Double Plays | Double plays the fielder took part in. |
| TP | Triple Plays | Triple plays the fielder took part in. |
| FPCT | Fielding Percentage | Share of chances handled cleanly. Near 1.000 for everyone at the top level, so it separates fielders poorly — it rewards limited range (balls never reached can't be misplayed). (PO + A) ÷ (PO + A + E) regulars sit ~.980+ |
| RF/9 | Range Factor per 9 Innings | Plays made (putouts + assists) per nine innings — a rough measure of how much ground a fielder covers, and less deceptive than fielding percentage. 9 × (PO + A) ÷ Innings |
| RF/G | Range Factor per Game | Plays made per game — the per-game companion to RF/9. (PO + A) ÷ Games |
| PB | Passed Balls | Catchable pitches a catcher failed to hold, letting a runner advance. |
| SB | Stolen Bases Allowed | Bases stolen with this catcher behind the plate — partly on the pitcher's ability to hold runners. |
| CS | Runners Caught Stealing | Would-be base stealers this catcher threw out. |
| CS% | Caught Stealing Percentage | Share of steal attempts the catcher erased. The headline catcher-throwing number. CS ÷ (SB + CS) league avg ~20%; 30%+ is elite |
| CI | Catcher's Interference | Times the catcher was charged with interfering with the batter. |
Pitching
| W | Wins | Pitcher wins. Team- and luck-dependent; kept for familiarity, not analysis. |
| L | Losses | Pitcher losses. |
| SV | Saves | Games saved. 30+ marks a full-time closer |
| SVO | Save Opportunities | Chances to record a save. Read next to SV for the conversion rate — blowing more than one in ten is shaky closing. |
| HLD | Holds | Holds — a setup reliever's save-equivalent. |
| BS | Blown Saves | Save opportunities lost. |
| G | Games | Appearances. |
| GS | Games Started | Starts. 30+ is a full starter season |
| GF | Games Finished | Games in which the pitcher recorded the final out for his team — the closer's counting stat. |
| QS | Quality Starts | Starts of six or more innings allowing three or fewer earned runs — did he keep the team in the game and go deep doing it. Read next to IP/G for the outing-length story. 20+ in a season is a workhorse; 25+ leads the league |
| RS | Run Support | Runs his team scored in his outings — the context that turns identical ERAs into different W-L records. |
| IR | Inherited Runners | Runners already on base when the reliever entered. |
| IRS | Inherited Runners Scored | Inherited runners who came around to score — they count against the previous pitcher's ERA, so stranding them is invisible in ERA but very real. stranding 70%+ of inherited runners is good relief work |
| CG | Complete Games | Complete games — increasingly rare. |
| SHO | Shutouts | Complete-game shutouts. |
| IP | Innings Pitched | Innings pitched, shown in the conventional .1/.2 thirds notation. Stored internally as outs so career totals sum exactly. 180+ IP is a durable starter season |
| IP/G | Innings per Game | Average innings pitched per appearance — a measure of outing length. Separates workhorse starters from openers and relievers. IP ÷ G ~5.5–6 solid starter; 6.5+ workhorse; ~1 typical reliever |
| TBF | Total Batters Faced | Batters faced — the pitcher's plate-appearance denominator for K% and BB%. |
| H | Hits Allowed | Hits allowed. |
| R | Runs Allowed | All runs allowed, earned or not. |
| ER | Earned Runs | Earned runs allowed. |
| HR | Home Runs Allowed | Home runs allowed. |
| BB | Walks Allowed | Walks issued. |
| IBB | Intentional Walks Issued | Intentional walks issued. |
| SO | Strikeouts | Batters struck out. 200+ over a season is elite for a starter |
| HBP | Hit Batters | Batters hit by pitch. |
| WP | Wild Pitches | Wild pitches. |
| BK | Balks | Balks. |
| Pit | Pitches Thrown | Total pitches thrown. |
| Str | Strikes | Pitches thrown for strikes (called, swinging, or fouled). |
| Str% | Strike Percentage | Strikes as a share of all pitches — a raw measure of living in the zone. Strikes ÷ Pitches league avg ~64% |
| SB | Stolen Bases Allowed | Stolen bases allowed while on the mound — how freely runners take off against him. |
| CS | Caught Stealing | Runners caught stealing while he pitched (credit shared with the catcher). |
| PK | Pickoffs | Runners picked off base. |
| GO | Ground Outs | Outs recorded on ground balls. |
| AO | Air Outs | Outs recorded on balls in the air. |
| GO/AO | Ground Out to Air Out Ratio | Ground outs per air out. Ground-ball pitchers run higher ratios and keep the ball in the park. GO ÷ AO league avg ~1.1; 1.5+ marks a ground-ball pitcher |
| K/9 | Strikeouts per 9 Innings | Strikeout rate per nine innings. K% (per batter faced) is slightly more accurate; K/9 remains the familiar form. SO × 9 ÷ IP league avg ~8.5; 10+ excellent |
| BB/9 | Walks per 9 Innings | Walk rate per nine innings. BB × 9 ÷ IP league avg ~3.2; under 2.0 elite control |
| HR/9 | Home Runs per 9 Innings | Home runs allowed per nine innings. HR × 9 ÷ IP league avg ~1.2 |
| H/9 | Hits per 9 Innings | Hits allowed per nine innings. H × 9 ÷ IP league avg ~8.5 |
| K/BB | Strikeout-to-Walk Ratio | Strikeouts per walk — command and dominance in one number. SO ÷ BB league avg ~2.8; 4+ elite |
| K% | Strikeout Rate | Strikeouts per batter faced — the more precise strikeout rate. SO ÷ TBF league avg ~22%; 28%+ elite |
| Sw | Swings Induced | Total swings taken against him. |
| Whf | Swings and Misses | Swings against him that missed entirely. |
| Whiff% | Whiff Rate | Share of swings against him that miss — bat-missing stuff, the leading indicator for strikeout rate. Misses ÷ Swings league avg ~24%; 30%+ elite stuff |
| BB% | Walk Rate | Walks per batter faced. BB ÷ TBF league avg ~8%; under 6% excellent |
| WHIP | Walks + Hits per Inning | Baserunners allowed per inning. (BB + H) ÷ IP league avg ~1.30; under 1.10 excellent |
| AVG | Batting Average Against | Opponents' batting average. league avg ~.245 |
| ERA | Earned Run Average | Earned runs allowed per nine innings. The classic pitching stat — real outcomes, but noisy: defense and sequencing luck are baked in. Read it next to FIP. ER × 9 ÷ IP league avg ~4.20; under 3.00 elite |
| FIP | Fielding Independent Pitching | What a pitcher's ERA would look like based only on what he controls — strikeouts, walks, hit batters, and home runs — with league-average results on balls in play. On the ERA scale. A pitcher whose ERA is far below his FIP is often getting defense/luck help. (13×HR + 3×(BB+HBP) − 2×SO) ÷ IP + constant league avg ~4.20; under 3.30 elite |
| xFIP | Expected FIP | FIP with the home-run component replaced by a league-average HR-per-fly-ball rate — useful because HR/FB is largely luck for most pitchers. Imported where available. |
| ERA- | ERA Minus | ERA on an index scale: 100 is league average and every point below is one percent better — park- and era-adjusted, so a 1968 season and a 2000 season compare cleanly. Imported, not computed here. 100 = average; 80 excellent; 70- Cy Young-caliber |
| FIP- | FIP Minus | FIP on the same 100-is-average index as ERA-. Imported, not computed here. 100 = average; 80 excellent |
| xERA | Expected ERA | Statcast's estimate of what his ERA should be from the quality of contact allowed (exit velocity and launch angle), on the ERA scale. A big gap under his real ERA suggests bad luck. compare to ERA: lower xERA suggests better than the results |
| xwOBA | Expected wOBA Against | Statcast's expected wOBA allowed, from strikeouts, walks, and quality of contact — the pitcher-side twin of the hitter's xwOBA. league avg ~.320; under .280 elite |
| xBA | Expected BA Against | Statcast's expected batting average allowed from quality of contact. |
| WAR | Wins Above Replacement | Total pitcher value versus a replacement-level arm, in wins. Imported from MLB's statsapi; other sites' WAR models will differ. 2+ solid starter; 4+ All-Star; 6+ Cy Young-caliber |