Mark
Flekken
GKNetherlands · Bayer 04 Leverkusen
Image: FootyLogos
Player dossierBundesliga
MarkFlekken
GKGoalkeeperGoalkeeper
- Club
- Bayer 04 Leverkusen
- League
- Bundesliga
- Nationality
- Netherlands
- Age
- 32
- Height
- 195 cm
- Foot
- Both
- Valued
- 27 May 2026
BundesligaReading the valuation
The market values Flekken at €6M. Model A, which never saw Flekken during training, estimates €5.1M: the market value is 17% above that estimate.
That is a factor of ×1.17. 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 €2.8M, 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
- 6,336
- Started
- 71/71
- Min / app
- 89
- Cards
- 2Y 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 Flekken…
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 €6M
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 485 goalkeepers
Dashed ring: the goalkeeper median (50th percentile)
Minutes, two years
Total club minutes in the two-year window: how much the player was used.
6,336 this player2,790 goalkeeper median88th 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
- Oct 2011
- Peak
- €12M
- Oct 2023
- Model target
- €6M
- May 2026
- Valuations
- 36
- 6 club changes
May 2026: €6M, Bayer 04 Leverkusen. Dotted lines mark the €2M, €10M and €30M tier boundaries.
Show as a table
| Date | Market value | Club |
|---|---|---|
| 2011-10-18 | €50k | Alemannia Aachen U19 |
| 2012-01-16 | €50k | Alemannia Aachen U19 |
| 2013-01-29 | €100k | Alemannia Aachen |
| 2013-03-11 | €200k | Alemannia Aachen |
| 2013-06-28 | €250k | Alemannia Aachen |
| 2014-01-20 | €250k | SpVgg Greuther Fürth |
| 2014-06-30 | €250k | SpVgg Greuther Fürth |
| 2015-01-13 | €200k | SpVgg Greuther Fürth |
| 2015-07-01 | €200k | SpVgg Greuther Fürth |
| 2016-02-11 | €200k | SpVgg Greuther Fürth |
| 2016-07-14 | €200k | MSV Duisburg |
| 2016-10-08 | €250k | MSV Duisburg |
| 2017-02-10 | €350k | MSV Duisburg |
| 2017-06-14 | €450k | MSV Duisburg |
| 2017-10-17 | €600k | MSV Duisburg |
| 2018-01-22 | €750k | MSV Duisburg |
| 2018-06-19 | €900k | MSV Duisburg |
| 2018-12-18 | €750k | SC Freiburg |
| 2019-06-05 | €600k | SC Freiburg |
| 2019-12-17 | €1.2M | SC Freiburg |
| 2020-04-08 | €950k | SC Freiburg |
| 2020-09-16 | €2M | SC Freiburg |
| 2021-02-10 | €2M | SC Freiburg |
| 2021-06-09 | €2.5M | SC Freiburg |
| 2021-10-07 | €4M | SC Freiburg |
| 2021-12-22 | €5.5M | SC Freiburg |
| 2022-06-09 | €7M | SC Freiburg |
| 2022-11-09 | €7M | SC Freiburg |
| 2023-06-22 | €10M | SC Freiburg |
| 2023-10-09 | €12M | Brentford FC |
| 2023-12-19 | €12M | Brentford FC |
| 2024-05-27 | €12M | Brentford FC |
| 2024-12-16 | €10M | Brentford FC |
| 2025-05-30 | €10M | Brentford FC |
| 2025-12-19 | €8M | Bayer 04 Leverkusen |
| 2026-05-27 | €6M | Bayer 04 Leverkusen |
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
- +0.157
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 53% of the 451 Bundesliga players.
See them in the Explorer →Goalkeepers, all leagues485 players · median €1M
Valued above 82% of the 485 goalkeepers.
See them in the Explorer →Where Flekken appears
Watchlists and the comparison tray are kept in this browser only.
Near this valuation closest observed values: same league, then same position
- SabitzerCMBorussia Dortmund · Bundesliga€6M
- AndrichDMBayer 04 Leverkusen · Bundesliga€6M
- PoschCB1.FSV Mainz 05 · Bundesliga€6M
- JakicDMFC Augsburg · Bundesliga€6M
- LenoGKFulham FC · goalkeepers€6M
- RulliGKOlympique Marseille · goalkeepers€6M
- BatallaGKRayo Vallecano · goalkeepers€6M
- SiveraGKDeportivo Alavés · goalkeepers€6M
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).