The 23-year-old defender has struggled to match the performances of his last two seasons during which he was rated as one of the best centre-backs in France.
"We've talked with him and he knows what he needs to do to get back to his best," Ligue1.com quotes him as saying.
"He's a top professional who has a great capacity for self-analysis."
Nkoulou joined Marseille from Monaco in 2011.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| C | Paris Saint-GermainPSG | 34 | 22 | 10 | 2 | 81 | 33 | 48 | 76 |
| 2 | MonacoMonaco | 34 | 20 | 7 | 7 | 68 | 42 | 26 | 67 |
| 3 | Brest | 34 | 17 | 10 | 7 | 53 | 34 | 19 | 61 |
| 4 | Lille | 34 | 16 | 11 | 7 | 52 | 34 | 18 | 59 |
| 5 | Nice | 34 | 15 | 10 | 9 | 40 | 29 | 11 | 55 |
| 6 | Lyon | 34 | 16 | 5 | 13 | 49 | 55 | -6 | 53 |
| 7 | Lens | 34 | 14 | 9 | 11 | 45 | 37 | 8 | 51 |
| 8 | Marseille | 34 | 13 | 11 | 10 | 52 | 41 | 11 | 50 |
| 9 | Reims | 34 | 13 | 8 | 13 | 42 | 47 | -5 | 47 |
| 10 | Rennes | 34 | 12 | 10 | 12 | 53 | 46 | 7 | 46 |
| 11 | Toulouse | 34 | 11 | 10 | 13 | 42 | 46 | -4 | 43 |
| 12 | Montpellier HSCMontpellier | 34 | 10 | 12 | 12 | 43 | 48 | -5 | 41 |
| 13 | StrasbourgStrasbourg | 34 | 10 | 9 | 15 | 38 | 50 | -12 | 39 |
| 14 | NantesNantes | 34 | 9 | 6 | 19 | 30 | 55 | -25 | 33 |
| 15 | Le HavreLe Havre | 34 | 7 | 11 | 16 | 34 | 45 | -11 | 32 |
| 16 | Lorient | 34 | 7 | 8 | 19 | 43 | 66 | -23 | 29 |
| 17 | Metz | 34 | 8 | 5 | 21 | 35 | 58 | -23 | 29 |
| R | Clermont | 34 | 5 | 10 | 19 | 26 | 60 | -34 | 25 |
| > Ligue 1 Full Table | |||||||||
