DEREK McInnes' decision to stick with Aberdeen rather than twist at Sunderland is a call which has sparked both debate and surprise in equal measure.

If it's a gamble that will pay off, we will find out in the coming weeks as the pursuit of the Holy Grail of the Europa League group stages, a long-standing target of McInnes, begins in just a few weeks. According to Jimmy Calderwood, the last man to do so with the Pittodrie clubs, the odds are becoming more and more stacked against him.

Taking Aberdeen to new heights was always going to be difficult for the 45-year-old. With successive second placings in the league, regular appearances in cup finals and the odd splash of silverware, repeating that run in the face of increased competition and striving for progression on the continent even if he kept all of his stars was far from straightforward. Factor in the loss of Jonny Hayes, Niall McGinn, Ryan Jack and now potentially Kenny McLean to Rangers, it's not just pushing an elephant up a hill but doing it backwards.

Aberdeen's second round qualifier first leg against either Kazakhstan’s Ordabasy or Siroki Brijeg of Bosnia and Herzegovina is not until July 13, but the deadline for registering new players for the round is July 7. For Calderwood, the man who guided Aberdeen through the group stages and into the last 32 against Bayern Munich in 2008, time is of the essence of McInnes is to get a squad knitted together quickly enough to satisfy the hankering for European football until Christmas.

"They are big, big players that Aberdeen have lost," said Calderwood. "I'm sure Derek will get it right and the chairman will help him. But it's not too long coming. Are they going to get these players in on time? They won't be where Derek will want them to be.

"We are still a small country. Sunderland is a fabulous club, as is Aberdeen. Martin Bain would have been a very good man for Derek if he'd gone, but obviously he knows he's at a great club.

"He's got two or three weeks for his players to bed in, but he'll get no sympathy. Whatever he's done in the past and all the good things, supporters just want to see cups and success. They've made it very difficult for themselves."

Calderwood recalls with fondness that season 10 years ago that ultimately culminated in a 5-1 hammering to Bayern Munich in the Allianz Arena. On the way there, Aberdeen drew with Lokomotiv Moscow, put up a plucky performance away to Atletico Madrid in a 2-0 reverse, spanked Copenhagen 4-0 and incredibly drew 2-2 with Bayern on home soil in the first leg.

Despite the sobering ending, the journey was stuff of dreams for Calderwood, his team and a band of supporters longing for something more in Europe than brief forays of disaster to fairly unglamorous outposts across eastern Europe. That dream can emerge once more as a reality according to the man himself.

"It was fantastic and unbelievable. I had a good career myself but to be up against those players, coaches and in these stadiums is what it's all about," he said.

"Aberdeen can get that again but there's not long to go. Four or five new players have to get into the way Derek wants his team to play. It's very, very quickly."