Czech keeper Jaroslav Drobný has not been offered an extended stay at the club. The former Fulham man has been with the Blues on a short-term contract but has not done enough to win a longer deal.
Boss Jim Magilton told the club site: "We thank Jaro for his time here and wish him well in the future."
Magilton is keen to recruit a senior goalkeeper to work alongside youngsters Shane Supple and Lewis Price.
Drobný's chances of winning a permanent deal looked slim after Magilton chose to bring Mike Pollitt in on loan from Wigan when both Supple and Price were injured. Pollitt's spell with the Blues was cut short when the Latics faced a goalkeeping injury crisis.