MLB Arbitration Analyzer

Overview

This tool provides a clear framework for estimating player salaries in arbitration and evaluating surplus value. It is built on an Excel dataset I created using information from FanGraphs (WAR and service time), ZiPS (2026 WAR projections), and Spotrac (2025 salaries). I then developed the model in Python and deployed it to Streamlit through GitHub, making it accessible for users to interact with. The data reflects the 2025–26 offseason, and each player’s performance, service time, and salary history were combined to construct formulas that simulate arbitration negotiations.

Note: This model uses WAR-based market valuations ($/WAR) as a framework to simulate arbitration negotiations. Outputs are designed to highlight relative differences in value rather than replicate literal arbitration case outcomes.

Player Ask

Weighted Average Performance (WAP) = 65% from 2025 WAR + 35% from 2026 projected WAR
Salary baselines by arbitration year:
Arb 1 = WAP × $4.0M per WAR
Arb 2 = WAP × $5.5M per WAR
Arb 3 = WAP × $7.0M per WAR
Free Agency = WAP × $9.0M per WAR

Team Offer

WAP = 80% from 2025 WAR + 20% from 2026 projected WAR
Salary baselines by arbitration year:
Arb 1 = WAP × $3.0M per WAR
Arb 2 = WAP × $4.0M per WAR
Arb 3 = WAP × $5.5M per WAR
Free Agency = WAP × $7.0M per WAR

Midpoint

(Player Ask + Team Offer) ÷ 2

Special Cases

If a team’s projected offer is negative, the result defaults to “Non-Tender.”
If either the player’s ask or the team’s offer falls between $10,000 and $750,000, both values default to the league minimum of $750,000.

Output

Player Ask
Team Offer
Midpoint
Projected Surplus Value (calculated as 2026 ZiPS WAR × $10M per WAR – Team Offer)

Conclusion

Overall, the tool serves as a strong indicator of how arbitration negotiations may unfold between teams and players. The formulas provide clear, data-driven estimates of potential outcomes, helping teams anticipate what to expect at the negotiation table. In addition, the model highlights players who may be undervalued, particularly those with modest asks but high projected surplus value.

Sample Results