João
Mendes
LBPortugal · Vitória Guimarães SC
Player dossierLiga Portugal
JoãoMendes
LBLeft-BackDefender
- Club
- Vitória Guimarães SC
- League
- Liga Portugal
- Nationality
- Portugal
- Age
- 26
- Height
- 179 cm
- Foot
- Left
- Valued
- 28 May 2026
Reading the valuation
The market values Mendes at €2.5M. Model A, which never saw Mendes during training, estimates €3.5M: the market value is 29% below that estimate.
That is a factor of ×1.42. Model A's typical held-out miss is ×1.50 either way, so this gap is within its usual error.
Without league and club, Model B estimates €5.1M, further from the market. Model B is usually further off (typical miss ×2.07): league and club explain much of how the market prices players.
A gap describes the model's arithmetic for this player's inputs, not what the player is worth.
- Apps
- 71
- Minutes
- 6,026
- Goals
- 1
- Assists
- 4
- Started
- 71/71
- Min / app
- 85
- Cards
- 17Y 0R
Club matches, two years to the valuation date
The Valuation Journey
What moves Model A
Asking the prediction API to explain Model A for Mendes…
SHAP describes the model's arithmetic for this player's inputs, not what causes market value. Model B can be explained only by the live service; Model A also has a published explanation for the research players.
Model A vs Model B against the observed €2.5M
Checking APIAsking the prediction API…
Held-out estimates come from cross-validation, with this player outside the training data: the honest comparison. Served models were refitted on every player, this one included, so they sit closer to the market. Shaded band: Model A's typical miss (×1.50 either way).
Player traitspercentiles vs 2,065 defenders
Dashed ring: the defender median (50th percentile)
Starts
Share of appearances started rather than entered from the bench.
100% this player83% defender median97th percentile
No passing, progression or defensive actions exist in the dataset, so no trait claims to measure them.
Valuation history every Transfermarkt valuation on record
- First valuation
- €400k
- Nov 2021
- Peak
- €3M
- May 2025
- Model target
- €2.5M
- May 2026
- Valuations
- 12
- 1 club change
May 2026: €2.5M, Vitória Guimarães SC. Dotted lines mark the €2M, €10M and €30M tier boundaries.
Show as a table
| Date | Market value | Club |
|---|---|---|
| 2021-11-05 | €400k | FC Porto B |
| 2022-04-01 | €450k | FC Porto B |
| 2022-06-27 | €675k | FC Porto B |
| 2022-12-28 | €825k | FC Porto B |
| 2023-06-28 | €1M | FC Porto B |
| 2023-12-14 | €1.2M | FC Porto B |
| 2024-06-20 | €1M | FC Porto B |
| 2024-10-08 | €2M | Vitória Guimarães SC |
| 2024-12-19 | €2.5M | Vitória Guimarães SC |
| 2025-05-30 | €3M | Vitória Guimarães SC |
| 2025-12-18 | €2.5M | Vitória Guimarães SC |
| 2026-05-28 | €2.5M | Vitória Guimarães SC |
Audit context group-level, not about this player
- Audit group
- UEFA
- Population gap, Model A
- +0.093 95% CI +0.063 to +0.124
- This player, market vs held-out A
- −0.348
The group comes from first-listed citizenship and is never a model input. Across the population, non-UEFA players' market values sit about 10% above Model A's held-out estimates, relative to UEFA players in the same leagues. One player's residual says nothing about that pattern (typical miss ×1.50), and none of it is evidence of discrimination: the target may itself be biased. Open the Fairness Audit
In context observed value among comparable players in this build
All players in the Terminal →Liga Portugal423 players · median €1M
Valued above 64% of the 423 Liga Portugal players.
See them in the Explorer →Defenders, all leagues2,065 players · median €2M
Valued above 54% of the 2,065 defenders.
See them in the Explorer →Where Mendes appears
Watchlists and the comparison tray are kept in this browser only.
Near this valuation closest observed values: same league, then same position
- GrillitschDMSC Braga · Liga Portugal€2.5M
- SamuAMVitória Guimarães SC · Liga Portugal€2.5M
- LivolantRWCasa Pia AC · Liga Portugal€2.5M
- VeronRWCD Nacional · Liga Portugal€2.5M
- GraditCBRC Lens · defenders€2.5M
- MainkaCB1.FC Heidenheim 1846 · defenders€2.5M
- CoufalRBTSG 1899 Hoffenheim · defenders€2.5M
- StarkCBSV Werder Bremen · defenders€2.5M
Counts and ranks of observed Transfermarkt values only; model errors are never ranked here. Full player export: Every player in the modelling population (D-011).