| When | Movement | Decision | Who |
|---|---|---|---|
| 03.06.2030 | Mainz 05 → | Contract expired — became a free agent | |
| 03.06.2030 | Free transfer listed | Left on a free after a year unsold on the transfer list | Board |
| 01.06.2029 | Transfer listed | Player requested to leave | Böhm Alexander |
| 02.03.2029 | 4y · $9.0M/y | Contract extension signed | |
| 01.03.2029 | 4y · $9.0M/y | Contract renewal offered | Böhm Alexander |
| 30.06.2027 | Köln → Mainz 05 | Returned from loan | |
| 02.08.2026 | 4y · $2.9M/y | Contract extension signed | |
| 01.08.2026 | 4y · $2.9M/y | Contract renewal offered | Werner Tobias |