The current window closes on August 31, though several clubs have made their feelings known that this is too late, with uncertainty over transfers proving a major distraction in the early weeks of the season.
It is understood that Premier League chairmen will be invited to take a vote at Thursday's AGM, with 14 out of 20 votes needed to pass the motion.
Speaking to BBC Radio 4, Harvey said: "Generally I think the mood is that it will be an improvement
"There are some significant concerns at some Premier League clubs around European competitions - the teams they are playing against being able to sign players after them.
"And from the EFL's perspective we have some real practical challenges to get over as well. Traditionally we start the season at different dates, so which start of the season are we going to use? Some of our clubs also survive on transfer income - selling players is an absolutely critical part of their business plan.
"There are a number of checks and balances we need to take to make sure this decision doesn't lead to some unintended consequences."