{"sport":"mlb","slug":"mike-slattery","bio":{"fullName":"Mike Slattery","position":"CF","team":null,"heightInches":74,"weightLbs":210,"birthDate":"1866-11-26","rookieSeason":1884,"lastSeason":1891,"status":"RET","externalIds":{"mlbam":"122315","chadwick":"93074014","retro":"slatm101","wikidata":"Q16031057"}},"draft":null,"statTables":[{"id":"batting","label":"Batting","columns":[{"key":"g"},{"key":"ab"},{"key":"r"},{"key":"h"},{"key":"doubles"},{"key":"triples"},{"key":"hr"},{"key":"rbi"},{"key":"sb"},{"key":"bb"},{"key":"so"},{"key":"avg"},{"key":"obp"},{"key":"slg"},{"key":"ops"}],"rows":[{"season":1884,"seasonType":"REG","team":"Boston Unions","gamesPlayed":106,"values":{"g":106,"ab":413,"r":60,"h":86,"doubles":6,"triples":2,"hr":0,"rbi":null,"sb":null,"bb":4,"so":null,"avg":0.208,"obp":null,"slg":0.232,"ops":null},"rowScope":"team"},{"season":1888,"seasonType":"REG","team":"SF","gamesPlayed":103,"values":{"g":103,"ab":391,"r":50,"h":96,"doubles":12,"triples":6,"hr":1,"rbi":35,"sb":26,"bb":13,"so":28,"avg":0.246,"obp":0.272,"slg":0.315,"ops":0.587},"rowScope":"team"},{"season":1889,"seasonType":"REG","team":"SF","gamesPlayed":12,"values":{"g":12,"ab":48,"r":7,"h":14,"doubles":2,"triples":0,"hr":1,"rbi":12,"sb":2,"bb":4,"so":3,"avg":0.292,"obp":0.346,"slg":0.396,"ops":0.742},"rowScope":"team"},{"season":1890,"seasonType":"REG","team":"New York Giants","gamesPlayed":97,"values":{"g":97,"ab":411,"r":80,"h":126,"doubles":20,"triples":11,"hr":5,"rbi":67,"sb":18,"bb":27,"so":25,"avg":0.307,"obp":0.352,"slg":0.445,"ops":0.797},"rowScope":"team"},{"season":1891,"seasonType":"REG","gamesPlayed":56,"gamesStarted":null,"values":{"g":56,"ab":218,"r":32,"h":50,"doubles":4,"triples":2,"hr":1,"rbi":21,"sb":7,"bb":14,"so":15,"avg":0.229,"slg":0.28,"obp":null,"ops":null},"team":"TOT","rowScope":"total"},{"season":1891,"seasonType":"REG","team":"CIN","gamesPlayed":41,"values":{"g":41,"ab":158,"r":24,"h":33,"doubles":3,"triples":2,"hr":1,"rbi":16,"sb":1,"bb":10,"so":10,"avg":0.209,"obp":0.256,"slg":0.272,"ops":0.528},"rowScope":"team"},{"season":1891,"seasonType":"REG","team":"Washington Senators","gamesPlayed":15,"values":{"g":15,"ab":60,"r":8,"h":17,"doubles":1,"triples":0,"hr":0,"rbi":5,"sb":6,"bb":4,"so":5,"avg":0.283,"obp":0.358,"slg":0.3,"ops":0.658},"rowScope":"team"}],"careerTotals":{"REG":{"g":374,"ab":1481,"r":229,"h":372,"doubles":44,"triples":21,"hr":8,"rbi":135,"sb":53,"bb":62,"so":71,"avg":0.251,"obp":0.284,"slg":0.325,"ops":0.609}}},{"id":"advanced","label":"Advanced (League-Relative)","columns":[{"key":"ops_plus","label":"OPS+","description":"On-base plus slugging vs the player's own season+league (100 = league average). Park-unadjusted; OBP uses a consistent (H+BB)/(AB+BB) rate. Higher is better.","format":"int","higherIsBetter":true},{"key":"era_plus","label":"ERA+","description":"Earned-run average vs the player's own season+league (100 = league average). Park-unadjusted. Higher is better.","format":"int","higherIsBetter":true}],"rows":[{"season":1884,"seasonType":"REG","team":"Boston Unions","values":{"ops_plus":57,"era_plus":null},"rowScope":"team"},{"season":1888,"seasonType":"REG","team":"SF","values":{"ops_plus":94,"era_plus":null},"rowScope":"team"},{"season":1889,"seasonType":"REG","team":"SF","values":{"ops_plus":115,"era_plus":null},"rowScope":"team"},{"season":1890,"seasonType":"REG","team":"New York Giants","values":{"ops_plus":121,"era_plus":null},"rowScope":"team"},{"season":1891,"seasonType":"REG","gamesPlayed":null,"gamesStarted":null,"values":{"ops_plus":null,"era_plus":null},"team":"TOT","rowScope":"total"},{"season":1891,"seasonType":"REG","team":"CIN","values":{"ops_plus":60,"era_plus":null},"rowScope":"team"},{"season":1891,"seasonType":"REG","team":"Washington Senators","values":{"ops_plus":91,"era_plus":null},"rowScope":"team"}],"careerTotals":{"REG":{"ops_plus":90,"era_plus":null}},"advancedMeta":{"method":"computed in-house from MLB StatsAPI season batting/pitching lines, normalized to each player's own (season, league) baseline","formulas":{"era_plus":"100 * lgERA / playerERA (league ERA = 9 * ΣER / ΣIP over the season+league)","ops_plus":"100 * (OBP/lgOBP + SLG/lgSLG - 1)","career_era_plus":"innings-weighted league ERA / career ERA (B-Ref method)","career_ops_plus":"AB-weighted OBP & SLG against AB-weighted league rates"},"caveats":["PARK-UNADJUSTED: no park-factor data exists in the corpus, so these are league-relative but not park-adjusted (true B-Ref ERA+/OPS+ also divide by a park factor)","OBP baseline uses a consistent (H+BB)/(AB+BB) reached-base rate for BOTH player and league — the source feed carries no HBP or SF, so this is not the full (H+BB+HBP)/(AB+BB+HBP+SF) OBP; SLG is exact from the hit-type columns","league resolved from team code + season (most-recently-founded franchise existing by that season); the same resolver builds the baseline and looks up the player, so ratios stay internally coherent","a (season, league) bucket below the sample floor (3000 AB batting / 1000 IP pitching) yields null — no noisy baselines","regular season only; postseason lines are excluded from league baselines and metrics","AL and NL and each historical/Negro league are normalized separately — never blended across leagues or eras"]}}],"dataSources":["MLB StatsAPI (statsapi.mlb.com — official public league API; facts only, raw payloads not republished)"],"generatedAt":"2026-07-03T08:11:48.216Z"}