Jan Ziolkowski
Value picture
Where the market, the likely price and the model estimates sit.
The model rates Jan Ziolkowski's performance-implied value at EUR 1.5M-11.9M, below the estimated acquisition range of EUR 9.5M-24.0M. Its 24-month market value projection is EUR 7.6M-30.7M. Confidence is low: no event-level data (xG, progressive actions) is available from the current free source, and injury history is unavailable.
Bargain Index: not assigned
What drives the score. Not a black box: each component and its level.
Insufficient sample (< 900 league minutes)
| Performance | Above average | 61.1th pct among DEF peers (age-neutral) |
| Age | Favorable | 21.1 years |
| Acquisition cost | Unfavorable | est. €15.6M vs market €12.0M |
| Expected appreciation | High | +29% over ~2 years (model) |
| Value gap | Very negative | weak predictor on its own |
| Development | High | breakout probability 43% |
| League translation | Big-five league | league coefficient 0.93 |
| Tactical fit | Not evaluated | Requires event/role data not available from the current free source. |
| Risk | High | |
| Data confidence | Low |
Bargain Index = percentile (among all evaluated players) of expected 2-year value relative to estimated cost. See methodology and backtests.
Market value history
Market value ≠ transfer fee ≠ acquisition cost.
Profile vs positional peers
Percentiles among 1269 evaluated DEF players with 900+ minutes.
Performance (last season, league)
- Minutes
- 507 (15% of available)
- Goals + assists / 90
- 0.00
- Context-adjusted G+A / 90
- 0.04
- xG, xA, progression
- Data unavailable
- Defensive actions
- Data unavailable
- Performance percentile
- 61 (Above average)
Adjusted = shrunk toward positional baseline for small samples, corrected for team dominance over opponents, expressed relative to positional peers in the same league.
Context
- League strength
- 0.93 (rank 4)
- Team strength (Elo)
- 1638
- Opponent strength
- 1486
- Possession, role
- Data unavailable
League strength 1.00 = average club of the big-five leagues. Elo includes continental matches.
Potential
- Development
- High
- Trajectory
- insufficient
- Breakout probability
- 43%
- Resale range (24m)
- €7.6M – €30.7M
Historical comparables (8): median 2-year value change +12% (IQR -35% to +103%).
Risk profile
Overall: High
- ▲Small sample: 507 league minutes last season.
- ▲Projection range among the widest 10% of evaluated players.
- ⚠Played under 40% of available league minutes (injury data unavailable, cause unknown).
- ⓘInjury history unavailable from current data source.
League translation
What happened to players who moved from this league to the big-five leagues (observed, not a forecast).
Already playing in a big-five league.
Output is relative to positional peers in each league. Movers are a selected group (clubs buy players who fit), so treat this as context, not a guarantee.
Season-by-season (domestic league)
Context-adjusted values are model outputs.
| Season | Club | League | Pos | Apps | Min | Min share | G | A | G+A/90 | Adj. G+A/90 | Opp. Elo | Team Elo | League str. |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2025/26 | Associazione Sportiva Roma | Serie A | CB | 18 | 507 | 15% | 0 | 0 | 0.00 | 0.04 | 1486 | 1638 | 0.93 |
Cups & continental competitions
| Season | Competition | Club | Apps | Min | G | A | Avg opp. Elo |
|---|---|---|---|---|---|---|---|
| 2025/26 | Uefa Europa League Qualifying | Legia Warszawa | 4 | 360 | 0 | 0 | 1442 |
| 2025/26 | Uefa Conference League Qualifying | Legia Warszawa | 2 | 205 | 0 | 1 | 1306 |
| 2025/26 | Uefa Europa League | Associazione Sportiva Roma | 4 | 189 | 1 | 0 | 1457 |
| 2025/26 | Italy Cup | Associazione Sportiva Roma | 1 | 45 | 0 | 0 | — |
| 2024/25 | Uefa Conference League Qualifying | Legia Warszawa | 1 | 33 | 0 | 0 | 1315 |
Small continental samples are shown for context only and are not over-weighted.
Historical comparables
Most similar profiles 2+ years ago (same position group) and what happened next. Chosen by similarity only — failures included.
| Player (then) | Age | Value then | ~2y later | Outcome |
|---|---|---|---|---|
| Matteo Gabbia Serie A · 2021 | 22 | €8.5M | €5.0M | fell |
| Marcelo Saracchi Bundesliga · 2019 | 21 | €10.0M | €5.5M | fell |
| Alessandro Zanoli Serie A · 2022 | 22 | €4.0M | €5.0M | rose |
| Djed Spence Ligue 1 · 2023 | 23 | €10.0M | €20.0M | rose |
| Javier Manquillo Premier League · 2015 | 21 | €6.0M | €4.0M | fell |
| Dayot Upamecano Bundesliga · 2017 | 19 | €7.5M | €30.0M | rose |
| Abner Laliga · 2023 | 23 | €7.0M | €7.0M | flat |
| Jeanuël Belocian Ligue 1 · 2023 | 18 | €7.0M | €15.0M | rose |
Transfer history
Fees as reported by the source; undisclosed fees shown as unknown, never estimated.
| Date | From | To | Fee | MV at time |
|---|---|---|---|---|
| 29 Aug 2025 | Legia Warszawa | Roma | €6.6M | €4.0M |
| 25 Jan 2023 | Legia II | Legia Warszawa | Unknown | Data unavailable |
| 1 Aug 2022 | Legia U19 | Legia II | Unknown | Data unavailable |
| 1 Jul 2022 | MKS Polonia U19 | Legia U19 | Unknown | Data unavailable |
MoneyballAI identifies statistical opportunities from available data. A player flagged as a potential bargain is not guaranteed to succeed, to transfer, to rise in value, or to generate resale profit. Market values, fees and contracts come from third-party sources; ranges are model estimates with stated confidence.