Mark Hughes feels relegation for Blackburn would have serious implications for their future.
Hughes spent four years at Ewood Park after leaving the Wales job to take up the reins in Lancashire.
Rovers currently sit six points clear of the drop zone but that gap could be closed if Hughes' Manchester City team beat them this Saturday at Eastlands.
"I know Blackburn very well from top to bottom and they cannot afford to go out of the Premier League," said Hughes.
"That would be disastrous.
"It has been a difficult season for them."
Established top 10 clubHughes' work at Rovers tempted City to take the plunge on him and the Welshman feels they have not been the same team since he departed.
"They were an established top 10 club when I was there and this year they have not been able to hit those heights."
But the former Manchester United and Chelsea striker has fond memories of his time at Blackburn and is pleased to see them picking up points again.
"Sam has come in and got them playing in a way that is helping them at the moment given their situation.
"They are getting points on the board, which is key.
"I still look out for their results. I had four good years there and enjoyed working with the people. They were a big part of the success I had there. It is a good club."