"We have been in discussion with John and his agent for many months, but in the last couple of days John has made it clear to us that he does not wish to sign a new contract,'' Rudge told the official website.
"John has explained to us that he has personal reasons for not wanting to stay. There is nothing we can do about that and unfortunately have to accept it.
"He could leave on a free transfer next summer, so it's obvious that if a significant offer comes in for him ahead of the August 31 deadline we would have to consider it."
Halls is without doubt a quality player who could play reguarly for a good premiership side. This makes things more disapointing for City who have premiership ambitions and will have desperately wanted to hang on to quality players like Halls.