Cox asked boss Dario Gradi about going out on loan, after the former Cardiff City defender foumd himself out of the first team after a run of poor performances.
Cox has not played in the last four games and the player said he wanted first team action so Gradi circulated his name to League clubs.
Gradi admitted he was disappointed that Cox and Julien Baudet have not been able to for a defensive partnership.
Gradi told the Sentinal "I had great hopes for Neil and Julien, but they have not done particularly well together," said Gradi.
"We conceded a lot of goals and it appears better with Billy Jones there.
"Julien is improving, although he is liable to make a mistake. I could use Neil in midfield, but the easier solution is to allow him to go out on loan."
"He is not going to get in the side at the moment, but is fit and, at his age, wants to play."
Gradi also went onto say "It means it is more likely we would resist a move for Billy Jones - we don't want him to go until the summer," added Gradi. "But we would be in the market for a centre-half now if we could find a suitable one."