David
Zec
CBSlovenia · Holstein Kiel
Player dossierBundesliga
DavidZec
CBCentre-BackDefender
- Club
- Holstein Kiel
- League
- Bundesliga
- Nationality
- Slovenia
- Age
- 25
- Height
- 190 cm
- Foot
- Right
- Valued
- 16 Dec 2025
BundesligaReading the valuation
The market values Zec at €2.5M. Model A, which never saw Zec during training, estimates €7.3M: the market value is 66% below that estimate.
That is a factor of ×2.92. 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 €6.5M, 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
- 28
- Minutes
- 2,505
- Goals
- 2
- Assists
- 1
- Started
- 28/28
- Min / app
- 89
- Cards
- 10Y 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 Zec…
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
- €50k
- Jul 2017
- Peak
- €2.5M
- Mar 2025
- Model target
- €2.5M
- Dec 2025
- Valuations
- 18
- 4 club changes
Dec 2025: €2.5M, Holstein Kiel. Dotted lines mark the €2M, €10M and €30M tier boundaries.
Show as a table
| Date | Market value | Club |
|---|---|---|
| 2017-07-16 | €50k | NK Triglav Kranj |
| 2018-02-21 | €200k | NK Triglav Kranj |
| 2019-02-12 | €200k | SL Benfica B |
| 2019-06-29 | €250k | SL Benfica B |
| 2019-12-31 | €100k | SL Benfica B |
| 2020-10-16 | €100k | Rukh Lviv |
| 2021-01-14 | €100k | Rukh Lviv |
| 2021-06-07 | €200k | Rukh Lviv |
| 2021-12-15 | €250k | NK Celje |
| 2022-06-27 | €250k | NK Celje |
| 2022-12-15 | €400k | NK Celje |
| 2023-05-25 | €500k | NK Celje |
| 2023-12-21 | €800k | NK Celje |
| 2024-05-24 | €800k | NK Celje |
| 2024-12-11 | €700k | NK Celje |
| 2025-03-27 | €2.5M | Holstein Kiel |
| 2025-06-05 | €2.5M | Holstein Kiel |
| 2025-12-16 | €2.5M | Holstein Kiel |
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
- −1.071
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 →Bundesliga451 players · median €5M
Valued above 25% of the 451 Bundesliga 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 Zec appears
Watchlists and the comparison tray are kept in this browser only.
Near this valuation closest observed values: same league, then same position
- KramaricSSTSG 1899 Hoffenheim · Bundesliga€2.5M
- BaumannGKTSG 1899 Hoffenheim · Bundesliga€2.5M
- EriksenAMVfL Wolfsburg · Bundesliga€2.5M
- MainkaCB1.FC Heidenheim 1846 · Bundesliga€2.5M
- GraditCBRC Lens · defenders€2.5M
- CoufalRBTSG 1899 Hoffenheim · defenders€2.5M
- StarkCBSV Werder Bremen · defenders€2.5M
- MataCBOlympique Lyon · 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).