Cardiff City and Leeds United are both chasing Gregan, but Peace warned: "Sean has stated he wants to leave us because he doesn't feel he will get adequate first team opportunities next season and wants regular football elsewhere.
"Therefore, the board has reluctantly accepted his written transfer request. Having paid £1.75 million to sign Sean only two years ago, we will only let him go if we receive an acceptable offer.
"Sean still has up to two years left on his contract and we are under no financial pressure to sell him or any of our players."