The 30-year-old, who spent last season on loan at Bolton Wanderers, was signed by Steve McClaren for £4.5m from Stoke City just 18 months ago.
Tuncay made just five appearances during his time in Germany without scoring a goal.
The striker only found the net once for the Trotters, in a Carling Cup game against Macclesfield.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| C | Bayer LeverkusenB. Leverkusen | 31 | 25 | 6 | 0 | 77 | 22 | 55 | 81 |
| 2 | Bayern MunichBayern | 31 | 22 | 3 | 6 | 89 | 38 | 51 | 69 |
| 3 | Stuttgart | 31 | 20 | 4 | 7 | 70 | 38 | 32 | 64 |
| 4 | RB Leipzig | 31 | 19 | 5 | 7 | 73 | 35 | 38 | 62 |
| 5 | Borussia DortmundDortmund | 31 | 16 | 9 | 6 | 59 | 39 | 20 | 57 |
| 6 | Eintracht FrankfurtFrankfurt | 31 | 11 | 12 | 8 | 47 | 42 | 5 | 45 |
| 7 | Freiburg | 31 | 11 | 7 | 13 | 43 | 55 | -12 | 40 |
| 8 | Augsburg | 31 | 10 | 9 | 12 | 48 | 52 | -4 | 39 |
| 9 | Hoffenheim | 31 | 11 | 6 | 14 | 55 | 63 | -8 | 39 |
| 10 | Heidenheim | 31 | 9 | 10 | 12 | 44 | 52 | -8 | 37 |
| 11 | Werder Bremen | 31 | 10 | 7 | 14 | 41 | 50 | -9 | 37 |
| 12 | Wolfsburg | 31 | 9 | 7 | 15 | 37 | 51 | -14 | 34 |
| 13 | Borussia MonchengladbachBorussia M'bach | 31 | 7 | 11 | 13 | 53 | 60 | -7 | 32 |
| 14 | Union BerlinUnion Berlin | 31 | 8 | 6 | 17 | 26 | 50 | -24 | 30 |
| 15 | VfL BochumVfL Bochum | 31 | 6 | 12 | 13 | 37 | 62 | -25 | 30 |
| 16 | Mainz 05Mainz | 31 | 5 | 13 | 13 | 32 | 49 | -17 | 28 |
| 17 | FC Koln | 31 | 4 | 11 | 16 | 24 | 54 | -30 | 23 |
| R | SV Darmstadt 98Darmstadt | 31 | 3 | 8 | 20 | 30 | 73 | -43 | 17 |
| > Bundesliga Full Table | |||||||||
