Reading boss Coppell disappointed to lose Seol
The South Korea international attacker moved to Craven Cottage in a swap for Liam Rosenior and Coppell said: "It has been obvious for some time that he wanted to move on.
"I would have loved him to stay but only if he was fully committed to us and I don't think he would have been. I had to make a decision and a decision has been made.
"Rosenior was at a dead end there and was part of an exchange offer put to us. He's an under-21 defender and can add to what we have.
"And he was a player who wanted to come here. That was important. We need players who are here by choice rather than here by force."