Carlisle will not be offering new deals to Marco Gbarssin, Kevan Hurst and Jason Price when their current contracts end.
Frenchman Gbarssin, 26, who signed a short-term contract to keep him with the club until the end of this season, fellow midfielder Hurst, 25, who joined United from Championship side Scunthorpe in the summer 2009 and former Swansea, Doncaster and Millwall striker Price, 33, have been released.
Manager Greg Abbott said: "We sent the lads out on loan because they needed regular football and that situation hasn't changed. That's not something that we can guarantee for them here.
"They've been fantastic to work with and we genuinely wish them all the very best as they move on."