Jon Taylor and Ryan Williams have both come to the end of thier contracts and rejected new deals to stay with the Millers, while Richie Towell will not be returning after his loan is up with parent club Brighton, where his contract is also up.
Speaking to the Advertiser, assistant boss Richie Barker said: "Tayls and Willo have decided that their futures lie elsewhere, We're no longer negotiating with them. There are no more contract talks planned."
"Unless something drastically changes, Richie has decided that he's going to explore other opportunities, The conversation in January didn't go the way everybody was hoping it would go. It was nobody's fault. The contract situation just couldn't be sorted at that particular time."
"The second half of the campaign didn't perhaps go as well for Richie as he would have liked, then we had the emergence of young Wilesy and, towards the end of the season, Crooksy,"
"With Semi also playing in midfield as well, it limited Richie's opportunities. The season sort of fizzled out for him really and he's now free to explore whatever he wants to do."
Meanwhile Joe Newell and Anthony Forde are still in talks about a new deal with the Millers.