The Toffees are in serious financial jeopardy, especially if a takeover from 777 Partners does not go through.
Thelwell told Everton's club website: "The reality is, given the regulations in place and the club's current financial position, we have to trade well. Working within such tight financial parameters makes the job extremely difficult.
Whilst we want to ensure the team is as competitive as possible, we cannot lose sight of our central objective to protect the long-term stability of the club. That does mean players will be sold, and also that every tool at our disposal will be used to secure new additions to the squad, including utilization of the loan market.
Both Sean and I understand the responsibility we have and that is a responsibility which has to be our priority. That may not be exciting to hear but, under our current circumstances, it is the right thing for Everton."