Acquisition Reliance

How much of a team's contention is carried by acquired (FA/trade) talent rather than home-grown — counted every season that talent stays on the roster.

What it measures

Each season, split the roster's WAR into the home-grown base (players who entered as the club's own amateur) and the acquired (FA + trade) WAR on top. Acquisition Reliance is the playoff probability your roster owes to that acquired talent — measured every season the players remain, not just the year they arrived. It answers "how much of this team's contention was bought rather than grown," summed across the tenure.

It is a roster-state stat: ~82% of it comes from acquired players in seasons after the year they were acquired, so it measures sustained reliance on the trade/FA market — not the timing or quality of individual deals (that's Acquisition Leverage).

The win curve + the split

Playoff probability is the same S-curve, P = σ(−9.09 + 0.200·W), maximal near the ~45-WAR threshold. Each season's reliance is the lift from the acquired WAR stacked on the home-grown base:

\[ \text{lev} = \big[\,P(W_\text{base}+W_\text{acq}) - P(W_\text{base})\,\big]\times 100 \] \[ \text{Acquisition Reliance} = \frac{\sum_\text{seasons}\text{lev}}{\sum W_\text{acq}}\quad\text{(playoff points per acquired WAR)} \] Win curve and acquired-talent reliance

How to read it — and why it predicts October

High = your playoff position rides on bought talent (the Moneyball A's, the bought Dodgers cores); low = a home-grown contender.
Predictiveness (team-WAR-controlled): +0.63 with reaching the playoffs, +0.36 with the pennant, +0.26 with the World Series — the strongest October predictor on the site. Sustaining a roster of high-leverage acquired talent, year after year, is what actually wins.
But as a per-GM skill it is only ~0.37 sticky (team-WAR-controlled) — much of it is "good teams stay good." For the repeatable executive decision skill, read Acquisition Leverage; this page is the roster-construction descriptor.

Worked example — the 2019 Dodgers

Inputs: home-grown base \(W_\text{base}=45.2\), acquired \(W_\text{acq}=16.6\), total = 61.8 WAR.

1. \(P(45.2)=\sigma(-9.09+0.200\times45.2)=\sigma(-0.05)=0.488\) — the home-grown core alone was a ~50% playoff team, right at the threshold.

2. \(P(61.8)=\sigma(3.27)=0.963\)

3. \(\text{lev}=(0.963-0.488)\times100 = +47.5\) playoff points the acquired talent was responsible for.

4. per acquired WAR: \(47.5/16.6 = \mathbf{2.9}\) — Los Angeles leaned heavily on bought talent sitting on the steepest part of the curve.

Fit on full team-seasons (≥100 games), 1985–2024/25. All figures are franchise-level outcomes credited to the decision-maker in the relevant year — see the GM profiles for per-executive numbers.

Rosternomics — quantifying front-office skill, attribution-clean. Follow @rosternomics on X. Decision-makers on record back to 1933; resource-controlled metrics (WAR & payroll) cover 1985–2026.
Data: FanGraphs (WAR), Baseball-Reference & the Chadwick Bureau register (rosters, IDs), the Lahman Database, Baseball America prospect rankings (via The Baseball Cube), and public payroll records. Transaction and trade data was obtained free of charge from and is copyrighted by Retrosheet. Executive birth/death data via Wikidata (CC0); bios are original. Emoji graphics by OpenMoji (CC BY-SA 4.0).
All figures are franchise-level outcomes credited to the decision-maker in the acquisition year — not solely attributable to one executive.