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December 2025
20 min read
48 MLB Pitchers Analyzed

Predicting Pitcher Injuries Before They Happen

A Data-Driven Approach to Protecting Your Most Valuable Assets

Every MLB team knows the sinking feeling: a star pitcher grabs his elbow mid-game, and suddenly a $200 million investment walks off the mound toward months of rehabilitation. What if you could see it coming?

84.2%
Detection Rate
24
Days Avg Warning
16/19
Pitchers Detected
48
Total Pitchers
MLB Pitcher Injury Detection Results - 84.2% detection rate

Triaxis AI detected pre-injury anomalies in 16 of 19 pitchers with available data

The $710 Million Problem

Baseball's Most Expensive Guessing Game

In 2025 alone, MLB teams have lost $710 million to injuries, with arm injuries accounting for $347 million - nearly half of all financial losses. Starting pitchers represent the largest share at over $343 million in lost value.

$1.5M
Average arm injury cost
12-18
Months Tommy John recovery
$58M+
Yankees/Dodgers arm injuries

Current Prevention Methods Fall Short

Pitch counts & innings limits
Crude measures that ignore individual variation
Subjective feel
"How does your arm feel today?"
Periodic medical imaging
Expensive, only after symptoms appear
Velocity monitoring
By the time it drops, damage is done

Watch the Explainer

A brief walkthrough of this pitcher injury detection research

The Body Tells the Truth

When a pitcher's arm is developing an injury, the body compensates - often before the pitcher consciously feels anything wrong. These compensations show up as subtle changes.

Velocity Patterns

Small but consistent changes in throwing speed

Release Point

Where the ball leaves their hand shifts

Arm Extension

How far they reach toward home plate

Pitch Selection

Unconsciously favoring pitches that hurt less

Our hypothesis: By analyzing every pitch a player throws and comparing it to their personal baseline, we can detect these compensations weeks before they become injuries.

Detection Performance

Among 19 Detectable Cases

Detected Before Injury16
Not Detected3
Detection Rate84.2%

*5 pitchers excluded due to insufficient pre-injury data (60+ day gaps)

Warning Time Distribution

Average lead time24 days
Median lead time24.5 days
Range2 to 40 days
<2 weeks
19%
2-4 weeks
44%
>4 weeks
37%
Detection to Injury timeline showing lead times
Key Finding

The Velocity Signal

Changes in average velocity are the strongest predictor of impending injury - appearing 3x more often in pre-injury signals.

Feature importance comparison showing velocity as strongest predictor

Injured vs Healthy Signals

Velocity Changes10.3% vs 3.2%
Release Point6.9% vs 2.6%
Pitch Selection10.3% vs 5.1%

Why Velocity Matters

When something is wrong with a pitcher's arm, velocity is often the first thing affected - even before the pitcher consciously compensates.

Statistical significance
3x more common
in pre-injury signals

Beyond the Radar Gun

"I don't need AI to tell me his velocity dropped." This critique misses the fundamental value. 81% of injury detections involved changes across 2+ feature categories. Zero detections were velocity-only.

What humans see vs what Triaxis AI sees - multi-dimensional analysis

Case Study: Jacob deGrom

Pre-injury signals detected 34 days before his UCL tear:

Major Shifts (|z|>2)
Plate location variance, fastball break
Obvious to analysis
Moderate (|z| 1.5-2)
Extension, slider usage
Subtle
Subtle (|z| 1-1.5)
Velocity, spin, median velocity
Invisible to naked eye

No coach watching the game would notice these combined shifts. Individually, each is within normal variation. Together, they form a pattern Triaxis AI recognizes as anomalous.

Understanding the Cases We Missed

Of the 3 pitchers we did not detect (among those with data), each case provides important context.

Near Miss

Max Scherzer

Anomaly score: 2.32

Detection threshold: 2.5

Literally on the edge of detection

Lowering threshold slightly would have caught him (with trade-offs).

Silent Failure

Shane McClanahan

Anomaly score: -0.22

Actually more consistent than normal

Required Tommy John surgery

Sudden structural failure rather than gradual degradation. Some UCL tears occur catastrophically.

Different Injury Type

Jesus Luzardo

Anomaly score: 1.49

Injury: Lumbar stress reaction

Spinal bone injury, not soft tissue

Bone injuries in the spine may not manifest through throwing mechanics changes.

Honest Assessment

The False Positive Question

"Will this just cry wolf constantly?" - A critical question for any detection system.

The Reality

Both healthy and pre-injury pitchers generate alerts at similar rates - approximately 2-3 alert events per 45-day monitoring period. A healthy ace like Framber Valdez triggered 46 alert days across his career data.

The Discriminator: Clustering Patterns

Injured pitchers
Clustered, escalating signals in 2-6 weeks before injury
Healthy pitchers
Scattered randomly throughout the season

Recommended Alert Response

Alert TypeFrequencyResponse
Single isolated alertCommonNote and monitor
2 alerts within 2 weeksElevatedMedical consultation
3+ alerts within 2 weeksHigh concernWorkload modification, imaging

Tiered Response Protocol

Single alerts are information; clustered alerts demand action.

Triaxis AI Alert Response Protocol flowchart
Score < 2.0
Continue Monitoring
Normal variation
Score 2.0-2.5
Watch Zone
Increase monitoring
Score > 2.5
Alert Zone
Medical evaluation
3+ in 14 days
Rest Consideration
Serious discussion

What We Can and Cannot Detect

Works Best For

  • Gradual-onset arm and shoulder injuries
  • Injuries preceded by mechanical compensation
  • Pitchers with consistent recent workload

Cannot Detect

  • Data gaps (no recent pitching to analyze)
  • Sudden catastrophic failures
  • Non-mechanical injuries (spinal bone stress)

The Question for MLB Teams

With an 84% detection rate and an average 24-day warning window, Triaxis AI provides teams with something they've never had before: actionable advance notice.

Would you rather know 24 days early, or find out when your ace grabs his elbow and walks off the mound?

Beyond Baseball

What This Research Actually Demonstrates

At its core, this paper validates the detection of subtle drift from personal baseline in high-frequency kinematic data from repetitive motion. The key insight: degradation announces itself through multi-dimensional compensation patterns before failure occurs.

The Pattern We Detected

  • - Personal baseline deviation over time
  • - Multi-dimensional compensation shifts
  • - Clustering of anomalies before failure
  • - Subtle changes invisible to observation

Systems With Similar Structure

  • - Industrial robot arm calibration drift
  • - Surgical instrument precision monitoring
  • - Autonomous vehicle control system health
  • - CNC machine tool wear detection
  • - Physical therapy recovery tracking

The common thread: Any system that performs repetitive motions and degrades gradually can benefit from baseline-relative anomaly detection. The body compensates before it fails. So do machines.

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