The new Spireites boss spoke to the squad this morning before his first training session.
He spoke on Tuesday about his aim of putting smiles back on faces of players at the Proact.
And today he told them to see his arrival as a fresh start and for those who haven't been playing, a chance to change their fortunes.
"I've said to the players this morning it's a clean slate," he said.
"We had a meeting this morning. I know most of the players. There's one or two faces I'm not familiar with.
"I just introduced myself and kept it brief. Forget about what's gone, concentrate on what we need to do, which is stay in the league.
"It's a new beginning, all managers are different.
"Forget what's gone and push on, get the results we need.
"I want them all to think they've got a chance of playing for me. I'm a different manager.
"Different players will impress me and they might show me what they can do.
"I've told them all, if you've not been involved, think you're going to be involved now, I'm giving everyone an opportunity.
"We are where we are, we've got to be realistic, but I'm hoping the players think they've got a chance.
"I might just pick a player who hasn't been involved, see something that means I have to involve him."
As he looks to put together a squad capable of keeping Chesterfield in the National League this season, Sheridan admits there may be both arrivals and departures.
"We'll assess that. I think we need to fill areas.
"Hopefully next week (will bring new faces). I'm in the process of asking people now, trying to get people now.
"I'm trying to be as honest as I can with players. If they're going to be sitting around, not figuring, not playing, I think it's only right they'll want to get out, they should themselves want to get out and play.
"That'll probably be middle of next week if I'm making those decisions."
Sheridan is likely to be without attacker Alex Kiwomya, who reinjured his hamstring on New Year's Day at Solihull, while Brad Barry is also a doubt according to the manager.