The 21-year-old, who is yet to make a first-team appearance for the Stamford Bridge club, spent the first half of the campaign on loan at Bristol Rovers, where he featured 14 times.
Walker joins fellow Chelsea youngsters Archange Nkumu and Billy Clifford at the Colchester Community Stadium.
Only Hartlepool, Scunthorpe and Carlisle have conceded more goals than Colchester in League One this season.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Liverpool | 12 | 10 | 1 | 1 | 24 | 8 | 16 | 31 |
| 2 | Manchester CityMan City | 12 | 7 | 2 | 3 | 22 | 17 | 5 | 23 |
| 3 | Chelsea | 12 | 6 | 4 | 2 | 23 | 14 | 9 | 22 |
| 4 | Arsenal | 12 | 6 | 4 | 2 | 21 | 12 | 9 | 22 |
| 5 | Brighton & Hove AlbionBrighton | 12 | 6 | 4 | 2 | 21 | 16 | 5 | 22 |
| 6 | Tottenham HotspurSpurs | 12 | 6 | 1 | 5 | 27 | 13 | 14 | 19 |
| 7 | Nottingham ForestNott'm Forest | 12 | 5 | 4 | 3 | 15 | 13 | 2 | 19 |
| 8 | Aston Villa | 12 | 5 | 4 | 3 | 19 | 19 | 0 | 19 |
| 9 | Fulham | 12 | 5 | 3 | 4 | 17 | 17 | 0 | 18 |
| 10 | Newcastle UnitedNewcastle | 12 | 5 | 3 | 4 | 13 | 13 | 0 | 18 |
| 11 | Brentford | 12 | 5 | 2 | 5 | 22 | 22 | 0 | 17 |
| 12 | Manchester UnitedMan Utd | 12 | 4 | 4 | 4 | 13 | 13 | 0 | 16 |
| 13 | Bournemouth | 12 | 4 | 3 | 5 | 16 | 17 | -1 | 15 |
| 14 | West Ham UnitedWest Ham | 12 | 4 | 3 | 5 | 15 | 19 | -4 | 15 |
| 15 | Everton | 12 | 2 | 5 | 5 | 10 | 17 | -7 | 11 |
| 16 | Leicester CityLeicester | 12 | 2 | 4 | 6 | 15 | 23 | -8 | 10 |
| 17 | Wolverhampton WanderersWolves | 12 | 2 | 3 | 7 | 20 | 28 | -8 | 9 |
| 18 | Ipswich TownIpswich | 12 | 1 | 6 | 5 | 13 | 23 | -10 | 9 |
| 19 | Crystal Palace | 12 | 1 | 5 | 6 | 10 | 17 | -7 | 8 |
| 20 | Southampton | 12 | 1 | 1 | 10 | 9 | 24 | -15 | 4 |
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