Loanees Evander Sno (Ajax), Patrick Agyemang (Queens Park Rangers) and Andrius Velicka (Glasgow Rangers) have also returned to their clubs.
Trundle, a £1m signing from Swansea City in the summer of 2007, spent this season on loan at his former club.
City caretaker manager Keith Millen said new boss Steve Coppell, who takes charge at the club next week, was involved in the decision making.
"Steve's overseen it, he's had an opinion on the loans and he's quite happy with what the club has agreed," said Millen.
"We're trying to help the young lads find clubs and Brian Wilson's come back from his injury and had six games in the reserves, which is great.
"But we feel that he needs to go somewhere to get first-team games and we can't promise him them."
Source: BBC Sport
Source: BBC Sport