The coaching staff has been strengthened with the addition of experienced fitness coach John Harbin.
Harbin, who worked at the club under Iain Dowie, will work alongside current fitness coach Dan Morton to ensure the players are as fit as possible for the start of the 2017/18 Sky Bet League One season.
Speaking about the appointment, Sheridan said: "I know John very well. He knows the club, he’s worked here before and he’s done well when he’s been here.
"He was successful under Iain Dowie when I was here as a player so he’s got different ideas and will work with young Dan and hopefully they will help each other.
"I’ve brought him in for the simple reason to make us better and stronger and be ready for a tough campaign."