April 29, 2026 — MLB Advanced Pitcher Stats

PropsBot added 5 new advanced pitcher metrics, and gave pitcher prop models direct access to the pitcher’s own long-horizon quality stats for the first time.

Five additional measurements now describe each pitcher’s quality:

• CSW% (Called Strikes + Whiffs Rate) — the percentage of pitches that result in either a called strike or a swinging strike. Widely regarded as one of the strongest single-stat indicators of a pitcher’s effectiveness, capturing both control and stuff.
• K% (Strikeout Rate) — strikeouts per batter faced. Distinct from K/9, which normalizes per innings rather than per batter.
• GB% (Ground Ball Rate) — the percentage of batted balls that are ground balls. Ground-ball pitchers generate more weak contact and double plays; fly-ball pitchers give up more home runs but more strikeouts.
• IP/Start (Innings per Start) — the average innings a pitcher records per game started. Long-outing pitchers face more batters and rack up more counting stats; short-outing pitchers exit before piling up strikeouts or runs.
• Pitches/Start — average pitch count per start. Captures workload, durability, and how managers handle the pitcher — all relevant to over/unders on counting stats.

Until today, pitcher prop models (Strikeouts, Hits Allowed, Walks, Earned Runs, Outs, Record a Win) had no direct access to the pitcher’s own long-horizon quality metrics — they only saw the pitcher’s recent rolling stats. That’s now fixed: pitcher prop models see all 16 pitcher quality features (the original 11 plus the 5 new ones above).

For batter prop models, the same 5 new features are now available describing the opposing pitcher.

11 of 18 MLB markets received upgraded models. The biggest improvements:

Pitcher markets:

• Pitcher Walks — large improvement
• Pitcher Record a Win — large improvement
• Pitcher Earned Runs — meaningful improvement
• Pitcher Strikeouts — modest improvement

Batter markets:

• Batter Stolen Bases — large improvement
• Batter Doubles — large improvement
• Batter Triples — meaningful improvement
• Batter Strikeouts — meaningful improvement
• Batter Hits + Runs + RBIs — modest improvement
• Batter Home Runs — modest improvement
• Batter Hits — modest improvement

The remaining 7 markets (Runs Scored, RBIs, Total Bases, Walks, Singles, Pitcher Hits Allowed, Pitcher Outs) kept their existing models because the new challengers didn’t clear the validation threshold.

• NFL, NBA, and NHL models are unaffected
• Existing batter prop features — rolling stats, platoon splits, BvP history, weather, performance states, game odds — unchanged
• The 7 markets above continue with their previous models