Wigan averaged only 11,498, even with Paul Jewell's side in the Championship top-three for almost the entire 2004-05 campaign.
But the chairman says they would have no trouble filling the 25,000 seats twice over for the Premiership pipe-opener against reigning champions Chelsea on August 13.
Whelan said: "I'm sure there will be a stampede for tickets once they go on general sale.
"People will see these fixtures and realise 'Yes, we really are going to have Chelsea, Arsenal and Manchester United here this season'.
"It is an incredible prospect for the fans, and it is quite a turnaround from when I took over in 1995.
"We had 1,500 at Springfield Park for my first match, against Hartlepool in the old Fourth Division.
"Now we will be starting against the champions of England, and what a mouth-watering prospect that is.
"Already the new strip has gone fantastically well, and it is brilliant to see so many people walking around Wigan with our shirt on.
"We sold around 4,000 replica shirts last year and this time we'll be looking at 14,000, and that's fantastic.
"This is an amazing chapter in the history of Wigan Athletic, and I'm sure many, many people will want to watch our every game in the Premier League.
"I know we've already had enquiries from football fans from Merseyside and Cheshire and the interest in the club is amazing."
Latics had 5,000 season tickets last term, but they look certain to double that figure come the big kick-off.
Meanwhile, reports linking Latics to former Preston North End striker Ricardo Fuller appear to be wide of the mark.
Fuller has been linked with a move away from Portsmouth.
And reports on the South Coast suggest Crystal Palace and Wigan are in the frame for the Jamaica star with Pompey wanting to sign Chelsea's Carlton Cole.
Jewell is extra keen to beef up his attacking options, and although last season's leading scorer Nathan Ellington expects to be fit for the start of the Premiership campaign after undergoing shoulder surgery, Jewell is poised to make several signings ahead of Wigan's top-flight challenge.
Whelan added: "The manager is working night and day to bring new faces in and there is a lot of hard work going on behind the scenes, so there should be some developments soon."
Wigan report back for pre-season training on Monday and their Republic of Ireland midfielder Graham Kavanagh says Latics will be ready for the challenge.
Kavanagh said: "The manager has us very well organised and it's not like we are all as green as grass. There are quite a few of us who have played in the Premiership.
"But our squad will need strengthening because we do not have the numbers to cope.
"It will not be easy to attract what we need.
"Scott Parker did not even want to talk to us by all accounts but it shows the calibre of player we are trying for and that's fantastic.
"I'm sure we'll be okay once the season starts."