Wigan chairman Dave Whelan is starting the search for a new manager and hopes to have the right man in place by the end of next week.
With a compensation package for Roberto Martinez agreed with Everton the Latics owner can get on with the task of finding a replacement for the Spaniard.
He has already received around 30 applications since he revealed last week he had given the Toffees permission to speak to Martinez.
"Roberto will be Everton manager in the next couple of days and that means we can start to interview for the position of manager of Wigan Athletic," Whelan told Press Association Sport.
"We have had a lot of applications and I think we will be choosing from the people who have applied.
"There are some very good candidates among them and with the quality that is there it is going to be difficult.
"It has got to be sorted out over the next nine or 10 days. We have got to get on. The Championship starts sooner than the Premier League and we have got a lot of games."
Although Wigan will be playing in Europe for the first time in thei history, courtesy of last month's FA Cup final win over Manchester City, Whelan has set his new manager just one priority: bouncing back from top-flight relegation immediately.
"We have got to get over it and get back in the Premier League as soon as possible," he added.
Names already linked with the vacancy include Brighton's Gus Poyet, Mike Phelan and Rene Meulensteen - both assistants to Sir Alex Ferguson at Manchester United - MK Dons' Karl Robinson and ex-Bolton boss Owen Coyle.