The 33-year-old, who had been with the club for six years, departed in the summer when financial restrictions meant that a new deal could not be offered.
"I believe that Steve is training with Salisbury. I don't hold that against him and it was his choice," Tisdale told the Western Morning News.
"We put him in a very difficult situation and not one I would like to do often with anybody. But he will have to look after himself and make the right decision for him.
"I believe that Steve has been with Salisbury for over a week now training with them and I don't know what the state of play is with his situation there, but he decided he was better off looking elsewhere rather than waiting."
It is not yet clear whether Salisbury will be offering the defender a contract.