Bullpen Watch
A bullpen-health tracker and save-probability dashboard that fans open before any late-inning situation to see who's actually available and likely to pitch.
Sabermetric-curious baseball fans who track reliever usage and want context before the 9th inning
- Live bullpen status for all 30 teams with consecutive-day usage heatmap
- Save-probability estimate before the 9th inning begins, factoring in usage
- Backtest mode showing how often a team's closer blew a save after a heavy workload week
- Push when a fan-favorite reliever is unavailable for tonight's game
Casual fans know starters get hurt; reliever attrition quietly shapes series like Royals-Orioles and rarely gets digestible coverage.
Niche but verified audience: InsidethePen, RotoWire, and FanGraphs have sustained multi-year bullpen-tracking products, showing real (small) demand, though Google Trends signal for the source query is tiny (~200 searches).MLB Bullpen Analytics & Usage Tracking 2026 | InsidethePen ↗Reliever Usage Report - RotoWire ↗
Market is crowded with established direct competitors: InsidethePen (premium membership site since 2022), BaseballAlerts bullpen fatigue tracker, DeepMetricAnalytics bullpen tracker, theCapper.io Bullpen IQ, RotoWire, and FanGraphs closer depth charts — all doing reliever availability and usage tracking.Bullpen Fatigue Tracker — Today's Closer Availability | Baseball Alerts ↗MLB Bullpen Availability & Fatigue Tracker — July 12, 2026 ↗Bullpen IQ — MLB Reliever Fatigue & Availability (2026) | thecapper.io ↗2026 Closer Depth Charts | RosterResource | FanGraphs Baseball ↗
Comparable tools (InsidethePen premium, RotoWire premium ~$30/yr+, FanGraphs) monetize via subscriptions, and InsidethePen just went 100% ad-free for paid members, proving willingness to pay exists — but mostly from fantasy/bettor users, not casual fans.MLB Bullpen Analytics & Usage Tracking 2026 | InsidethePen ↗
Bullpen attrition is a structural, season-long, and year-over-year MLB story; InsidethePen has operated since 2022 and the problem is built into the 162-game schedule, giving strong multi-season durability.MLB Bullpen Analytics & Usage Tracking 2026 | InsidethePen ↗
Buildable from public Statcast/MLB pitch data and basic rest/fatigue heuristics, but competing on data freshness and modeling quality against established trackers (InsidethePen's 33,000-appearance fatigue rebuild) is non-trivial.MLB Bullpen Analytics & Usage Tracking 2026 | InsidethePen ↗