However, Edwin van der Sar suffered a groin problem during the weekend FA Cup tie against Portsmouth, leading to his substitution at half time.
Tomasz Kuszczak replaced the Dutchman but then got sent off for a foul on Milan Baros, meaning United face the possibility of having to throw Foster in at the deep end.
"We had a good chance of someone but maybe that's not going to happen now," Coleman told The Coventry Telegraph.
"I will discuss it with the chairman.
"I was quite certain that we would have a new face last week and now it doesn't look like it."