The 31-year-old, who was signed by Evans when he was in charge of the Sussex club, rejected a new contract at Town and is attracting interest from several clubs, including the Millers, who have shown him around their new New York Stadium in a bid to entice him to South Yorkshire.
"Scott is an outstanding goalkeeper," Evans said. "He has a huge presence, his distribution is excellent and his kicking is a real asset but we are only one of a number of clubs in League One and Two who want to sign him.
"At the end of last season my goalkeeping coach Andy Dibble said Scott would be his first-choice new goalkeeper but I had to say to him the lad would, in my opinion, be staying at Crawley, but that has turned out not to be the case, that was a big surprise to me.
"I have now met Scott, showed him around the New York Stadium and of course the excellent training facilities. I have no doubt he was very impressed but he has a number of good clubs talking to him and I understand it is a big decision for him and his family.
"He has promised all the interested clubs that he will make a decision this week. He would be a great signing but I have a very good alternative in mind if he decides his future is elsewhere. I really thought the lad would stay where he was and obviously I hope my last 18 months with him will give us an edge but it's football and you just never know."