The former Oldham and Tranmere chief led the Millers to successive promotions in 2000 and 2001 during his eight-year spell at the club.
The 56-year-old left Rotherham by mutual consent in January 2005 when the club were 12 points adrift of safety in the Championship.
He told BBC Radio Sheffield: "I've already dropped in my CV. I'm up for the job if they want to give it me.
"I took them to the Championship the last time I was there and, who knows, maybe we can do it all again. I absolutely love the club."