"I am disappointed I have had to read about other clubs talking about signing one of my players," said Coppell.
"But it is a fact of life that your players are subject to interest from the big boys."
Sidwell has 12 months to run on his current contract but teams are circling. Reading are said to have offered him a new deal but there is a clause in his current contract that allows clubs that offer £2m+ are allowed to speak to the player.
Man City have made such an offer and reports suggest they are holding talks with Sidwell. Charlton are also interested.