He said: "Blackburn are in the same situation as I was in this time last year, and I decided I had to make a change and sack the manager even though he had only been there for a short time.
"I know the feeling, it is awful when you have to do it but although it is not a nice thing at all sometimes you are left with little choice because of the importance of staying up.
"A decision was needed. There becomes a deadline when you are in the bottom two, when after a certain date it is very hard to climb out of it. Blackburn Rovers are in a similar boat.
"As a chairman you really feel these pressures, they are enormous."
He insists he is rooting for a Rovers' recovery in the second half of the season, as long as it is not at the expense of his own club, admitting the prospect of Championship football is not a pretty one for any Premier League chairman.
"There is massive pressure on chairmen to succeed nowadays," said Whelan. "The Premier League is the best league in the world and to lose that status would be devastating for anyone.
"For the majority of clubs now the priority every year is survival. There is awful lot of money at stake now and that is very important to clubs like us, Blackburn and Bolton.
"Saturday is a huge game for both of us. Hopefully Blackburn bring a lot of fans and help to make it a great atmosphere."