Morsy is a free agent after turning down the offer of a new contract but the Burslem club are entitled to a fee for the former Wolves trainee as he is under the age of 24.
Vale chairman Norman Smurthwaite called Chesterfield's initial offer for Morsy "insulting" but the Spireites have had a second sum accepted by the League One newcomers.
Morsy's agent Matt Kleinman has revealed the player is in talks with Paul Cook's side and he expects the 21-year-old's move to the Proact Stadium to be completed early next week.
"A deal has been agreed between Chesterfield and Port Vale so it is just up to us to agree personal terms and I don't think that will be a problem," Kleinman said.
"I think we are very close to agreeing personal terms and the player should hopefully be signing pretty quickly, maybe within the next 72 hours or so.
"I think Port Vale have been very good in all of this and we are close to making it happen. I don't think there will be a problem in it going through."