Baseball Savant Expected Stats & Statcast Metrics

[grovecj]

Overview

Integrate with Baseball Savant to fetch expected statistics (xBA, xSLG, xwOBA) and Statcast metrics (exit velocity, barrel%, hard hit%, sprint speed).

Parent Issue

Part of #94 (WAR and Advanced Stats)

Data Source

Baseball Savant Expected Statistics Leaderboard:

https://baseballsavant.mlb.com/leaderboard/expected_statistics?type=batter&year={year}&min=q&csv=true

Fields to Ingest

Expected Stats (Batting):

• xba - Expected Batting Average
• xslg - Expected Slugging
• xwoba - Expected wOBA
• xwobacon - Expected wOBA on Contact

Statcast Metrics (Batting):

• avg_exit_velocity - Average Exit Velocity
• avg_launch_angle - Average Launch Angle
• barrel_pct - Barrel %
• hard_hit_pct - Hard Hit %
• sprint_speed - Sprint Speed

Statcast Metrics (Pitching):

• avg_exit_velocity_against - Exit Velocity Against
• hard_hit_pct_against - Hard Hit % Against
• whiff_pct - Whiff %
• chase_pct - Chase %

Current Entity Fields

These columns already exist in PlayerBattingStats (from V12 migration):

• xba, xslg, xwoba
• avg_exit_velocity, avg_launch_angle, barrel_pct, hard_hit_pct
• sprint_speed

And in PlayerPitchingStats:

• avg_exit_velocity_against, hard_hit_pct_against
• whiff_pct, chase_pct

These fields exist but are NOT currently populated!

Files to Create/Modify

Modify: ingestion/client/BaseballSavantClient.java

Add methods:

public Map<Integer, ExpectedStats> getExpectedStatsByPlayerId(Integer season);
public Map<Integer, StatcastMetrics> getStatcastMetricsByPlayerId(Integer season);

Create: ingestion/client/dto/ExpectedStatsData.java

public record ExpectedStatsData(
    Integer playerId,
    BigDecimal xba,
    BigDecimal xslg,
    BigDecimal xwoba,
    BigDecimal avgExitVelocity,
    BigDecimal avgLaunchAngle,
    BigDecimal barrelPct,
    BigDecimal hardHitPct,
    BigDecimal sprintSpeed
) {}

Create: ingestion/service/StatcastIngestionService.java

@Service
public class StatcastIngestionService {
    public int syncExpectedStats(Integer season);
    public int syncStatcastMetrics(Integer season);
}

Modify: ingestion/mapper/StatsMapper.java

Add method:

public void applyStatcastMetrics(PlayerBattingStats stats, ExpectedStatsData data);
public void applyStatcastMetrics(PlayerPitchingStats stats, PitchingStatcastData data);

Sync Strategy

• Weekly sync (with OAA in Baseball Savant OAA Integration #172)
• Statcast data updates after each game but aggregates change slowly
• Expected stats are season-level, update less frequently

Test Cases

• CSV parsing for all expected stats fields
• Player mapping works correctly
• Null/missing values handled gracefully
• Updates existing stats without overwriting other fields

Acceptance Criteria

• xBA, xSLG, xwOBA populated on batting stats
• Exit velocity, barrel%, hard hit% populated
• Sprint speed populated
• Pitching Statcast metrics populated
• Mapper tests for new apply methods

Dependencies

• Baseball Savant OAA Integration #172 (Baseball Savant OAA Integration) - Same client, can share infrastructure

Notes

The ExpectedStatsResponse.java and SeasonAdvancedResponse.java DTOs already exist but aren't integrated. This issue completes that integration.