Deal done for Chelsea keeper.
After two successful six month loan spells in north Essex, Walker has signed permanently from Chelsea, subject to the paperwork being ratified by the relevant bodies.
The second of those loans ended on Sunday, and the U's have moved quickly to secure the services of the twenty two year old in the current transfer window.
In the January window, the U's have now secured Walker, Dominic Vose and Alex Gilbey on new contracts and have extended the loan of Luke Garbutt from Everton.
Boss Joe Dunne was pleased with the news, saying: "I'm delighted that we've signed Sam for the next eighteen months.
"He is another young and hungry young footballer who has decided to come here and play, which is great testament to what we are doing here at Colchester United.
"He has done fantastically well for us over the past year but he is still improving and will get even better in the right environment for development.
"He will certainly have that here and he has a great support network, with our goalkeeper coach George Bankole and the other keepers he works with every day."