The International Rugby Board are taking steps to avoid a repeat of the scenario that sees England face New Zealand in the first Test of next year's summer tour with a weakened team.
Stuart Lancaster's side open the series on June 7, just seven days after the Aviva Premiership final is staged at Twickenham.
The proximity of the dates means head coach Lancaster is resigned to being unable to field his first-choice starting XV until the second Test on June 14.
IRB chief executive Brett Gosper regrets the confusion that arose over when the international window opens and hopes to prevent it from happening again.
"It's unfortunate, but it's the product of a crowded season. These calendars were decided some years ago and everyone was involved in that," Gosper said.
"I believe there was a little bit of confusion on behalf of some of the unions as to what the beginning of the window was in June.
"It's unfortunate that the two unions couldn't find a solution to the problem and it does look like England won't take a full strength side.
"We tried to move it but there were broadcast and planning elements in place that meant we couldn't.
"We're looking at the windows at the moment to see if we can find a better balanced calendar. It's a very crowded season."
Gosper is also "optimistic" that the dispute over European club rugby will be resolved.
All Six Nations unions apart from England have announced they are to set up a 20-team successor to the Heineken Cup in a development that threatens to isolate the Aviva Premiership clubs.
"We're following and monitoring it. We're optimistic that the parties will come together at some point," Gosper said.
"We're optimistic there will be a strong European competition and everyone will find a common ground.
"It's certainly moved towards agreement on a number of issues and we hope it continues in that way. We hope all nations are represented.
"We're not involved because we think it can be worked out by the people involved and we're heading in that direction. No one has asked us to be involved."