The 31-year-old has made just one Premier League start for the Hammers since joining them from Marseille in the summer.
Rennes will become the sixth Ligue 1 side that Diarra has represented.
He has also enjoyed stints at Le Havre, Bastia, Lens, Lyon and Bordeaux.
Diarra, who has been capped 44 times by France at senior international level, is under contract at Upton Park until June 2015.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Manchester CityMan City | 3 | 3 | 0 | 0 | 9 | 2 | 7 | 9 |
| 2 | Liverpool | 3 | 3 | 0 | 0 | 7 | 0 | 7 | 9 |
| 3 | Brighton & Hove AlbionBrighton | 3 | 2 | 1 | 0 | 6 | 2 | 4 | 7 |
| 4 | Arsenal | 3 | 2 | 1 | 0 | 5 | 1 | 4 | 7 |
| 5 | Newcastle UnitedNewcastle | 3 | 2 | 1 | 0 | 4 | 2 | 2 | 7 |
| 6 | Brentford | 3 | 2 | 0 | 1 | 5 | 4 | 1 | 6 |
| 7 | Aston Villa | 3 | 2 | 0 | 1 | 4 | 4 | 0 | 6 |
| 8 | Bournemouth | 3 | 1 | 2 | 0 | 5 | 4 | 1 | 5 |
| 9 | Nottingham ForestNott'm Forest | 3 | 1 | 2 | 0 | 3 | 2 | 1 | 5 |
| 10 | Tottenham HotspurSpurs | 3 | 1 | 1 | 1 | 6 | 3 | 3 | 4 |
| 11 | Chelsea | 3 | 1 | 1 | 1 | 7 | 5 | 2 | 4 |
| 12 | Fulham | 3 | 1 | 1 | 1 | 3 | 3 | 0 | 4 |
| 13 | West Ham UnitedWest Ham | 3 | 1 | 0 | 2 | 4 | 5 | -1 | 3 |
| 14 | Manchester UnitedMan Utd | 3 | 1 | 0 | 2 | 2 | 5 | -3 | 3 |
| 15 | Leicester CityLeicester | 3 | 0 | 1 | 2 | 3 | 5 | -2 | 1 |
| 16 | Crystal Palace | 3 | 0 | 1 | 2 | 2 | 5 | -3 | 1 |
| 17 | Ipswich TownIpswich | 3 | 0 | 1 | 2 | 2 | 7 | -5 | 1 |
| 18 | Wolverhampton WanderersWolves | 3 | 0 | 1 | 2 | 3 | 9 | -6 | 1 |
| 19 | Southampton | 3 | 0 | 0 | 3 | 1 | 5 | -4 | 0 |
| 20 | Everton | 3 | 0 | 0 | 3 | 2 | 10 | -8 | 0 |
| > Premier League Full Table | |||||||||
