I think it's cheating a bit, you are using the game system in a way it is unintended. In real life the board would let the player go.
A fairer way of overriding a transfer for a player, either by the board accepting it or a team matching the release clause is offering a better contract. If the player renews he won't move regardless of having the transfer bid accepted. I think it's a more realistic way of preventing players to leave.
Just offer the player a new contract
In real life they would be looking to re-negotiate, especially if their bid was accepted in the first place.