Lucas
Rosa
RBBrazil · Ajax Amsterdam
Player dossierEredivisie
LucasRosa
RBRight-BackDefender
- Club
- Ajax Amsterdam
- League
- Eredivisie
- Nationality
- Brazil
- Age
- 26
- Height
- 177 cm
- Foot
- Right
- Valued
- 28 May 2026
EredivisieReading the valuation
The market values Rosa at €5M. Model A, which never saw Rosa during training, estimates €3.1M: the market value is 64% above that estimate.
That is a factor of ×1.64. Model A's typical held-out miss is ×1.50 either way, so this gap is larger than its usual error.
Without league and club, Model B estimates €4.2M, closer to the market here, although it is usually further off (typical miss ×2.07).
A gap describes the model's arithmetic for this player's inputs, not what the player is worth.
- Apps
- 62
- Minutes
- 4,969
- Goals
- 0
- Assists
- 3
- Started
- 57/62
- Min / app
- 80
- Cards
- 13Y 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 Rosa…
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 €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)
Minutes, two years
Total club minutes in the two-year window: how much the player was used.
4,969 this player2,860 defender median83rd 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
- €100k
- Jun 2019
- Peak
- €5M
- May 2026
- Model target
- €5M
- May 2026
- Valuations
- 17
- 4 club changes
May 2026: €5M, Ajax Amsterdam. Dotted lines mark the €2M, €10M and €30M tier boundaries.
Show as a table
| Date | Market value | Club |
|---|---|---|
| 2019-06-17 | €100k | Juventus Primavera |
| 2019-12-16 | €125k | Juventus U23 |
| 2020-07-24 | €150k | Juventus U23 |
| 2021-01-11 | €150k | Juventus U23 |
| 2021-06-21 | €150k | Juventus U23 |
| 2021-12-30 | €150k | Real Valladolid Promesas |
| 2022-06-29 | €150k | Real Valladolid Promesas |
| 2022-11-07 | €1M | Real Valladolid CF |
| 2023-06-13 | €1M | Real Valladolid CF |
| 2023-12-20 | €1.2M | Real Valladolid CF |
| 2024-06-24 | €1.2M | Real Valladolid CF |
| 2024-10-11 | €2M | Real Valladolid CF |
| 2024-12-27 | €2M | Real Valladolid CF |
| 2025-03-28 | €3M | Ajax Amsterdam |
| 2025-05-28 | €3M | Ajax Amsterdam |
| 2025-12-02 | €4M | Ajax Amsterdam |
| 2026-05-28 | €5M | Ajax Amsterdam |
Audit context group-level, not about this player
- Audit group
- non-UEFA
- Population gap, Model A
- +0.093 95% CI +0.063 to +0.124
- This player, market vs held-out A
- +0.494
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 →Eredivisie425 players · median €1M
Valued above 80% of the 425 Eredivisie players.
See them in the Explorer →Defenders, all leagues2,065 players · median €2M
Valued above 70% of the 2,065 defenders.
See them in the Explorer →Where Rosa appears
Watchlists and the comparison tray are kept in this browser only.
Near this valuation closest observed values: same league, then same position
- WellenreutherGKFeyenoord Rotterdam · Eredivisie€5M
- JarosGKAjax Amsterdam · Eredivisie€5M
- RegeerDMAjax Amsterdam · Eredivisie€5M
- MeerveldAMSC Heerenveen · Eredivisie€5M
- OrbánCBRB Leipzig · defenders€5M
- GinterCBSC Freiburg · defenders€5M
- GuerreiroLBBayern Munich · defenders€5M
- TarkowskiCBEverton FC · defenders€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).