Jae-sung
Lee
AMKorea, South · 1.FSV Mainz 05
Player dossierBundesliga
Jae-sungLee
AMAttacking MidfieldMidfield
- Club
- 1.FSV Mainz 05
- League
- Bundesliga
- Nationality
- Korea, South
- Age
- 33
- Height
- 180 cm
- Foot
- Left
- Valued
- 27 May 2026
BundesligaReading the valuation
The market values Lee at €2M. Model A, which never saw Lee during training, estimates €2.1M: the market value is 3% below that estimate.
That is a factor of ×1.03. 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 €1.2M, 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
- 66
- Minutes
- 5,225
- Goals
- 12
- Assists
- 11
- Started
- 61/66
- Min / app
- 79
- Cards
- 8Y 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 Lee…
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 €2M
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 1,687 midfielders
Dashed ring: the midfielder median (50th percentile)
Starts
Share of appearances started rather than entered from the bench.
92% this player69% midfielder median90th 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
- Mar 2014
- Peak
- €4M
- Mar 2023
- Model target
- €2M
- May 2026
- Valuations
- 25
- 2 club changes
May 2026: €2M, 1.FSV Mainz 05. Dotted lines mark the €2M, €10M and €30M tier boundaries.
Show as a table
| Date | Market value | Club |
|---|---|---|
| 2014-03-13 | €50k | Jeonbuk Hyundai Motors |
| 2014-07-01 | €100k | Jeonbuk Hyundai Motors |
| 2015-01-01 | €500k | Jeonbuk Hyundai Motors |
| 2016-10-04 | €1M | Jeonbuk Hyundai Motors |
| 2017-12-15 | €2M | Jeonbuk Hyundai Motors |
| 2018-08-21 | €2M | Holstein Kiel |
| 2019-01-08 | €2M | Holstein Kiel |
| 2019-06-12 | €1.5M | Holstein Kiel |
| 2019-12-13 | €2M | Holstein Kiel |
| 2020-04-08 | €1.6M | Holstein Kiel |
| 2020-07-15 | €2M | Holstein Kiel |
| 2021-02-08 | €3M | Holstein Kiel |
| 2021-06-16 | €3M | Holstein Kiel |
| 2021-12-22 | €3.5M | 1.FSV Mainz 05 |
| 2022-06-09 | €3M | 1.FSV Mainz 05 |
| 2022-11-09 | €3M | 1.FSV Mainz 05 |
| 2023-03-29 | €4M | 1.FSV Mainz 05 |
| 2023-06-22 | €4M | 1.FSV Mainz 05 |
| 2023-10-18 | €3M | 1.FSV Mainz 05 |
| 2023-12-14 | €3M | 1.FSV Mainz 05 |
| 2024-05-29 | €2.5M | 1.FSV Mainz 05 |
| 2024-12-20 | €2.5M | 1.FSV Mainz 05 |
| 2025-06-05 | €2.5M | 1.FSV Mainz 05 |
| 2025-12-19 | €2M | 1.FSV Mainz 05 |
| 2026-05-27 | €2M | 1.FSV Mainz 05 |
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
- −0.029
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 19% of the 451 Bundesliga players.
See them in the Explorer →Midfielders, all leagues1,687 players · median €2M
Valued above 46% of the 1,687 midfielders.
See them in the Explorer →Where Lee appears
Watchlists and the comparison tray are kept in this browser only.
Near this valuation closest observed values: same league, then same position
- GünterLBSC Freiburg · Bundesliga€2M
- RönnowGK1.FC Union Berlin · Bundesliga€2M
- KohrCB1.FSV Mainz 05 · Bundesliga€2M
- KhediraDM1.FC Union Berlin · Bundesliga€2M
- GündoğanCMGalatasaray · midfielders€2M
- GudeljDMSevilla FC · midfielders€2M
- HazardAMRSC Anderlecht · midfielders€2M
- McGregorDMCeltic FC · midfielders€2M
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).