Manager Greg Abbott has decided to release three trialists following Carlisle's 3-0 friendly defeat to Barclays Premier League side Newcastle.
Defender Nick Wood and midfielders Patrick Cregg and Billy Gibson have all been told that they will not be required for the rest of pre-season training.
Abbott told the club's official website: "We have had to make some difficult decisions, because some of these lads have been with us for a couple of weeks now.
"They have all done really well, but it is time for us to start to work with and concentrate on the first team squad as we head towards the start of the season. These lads are all good players, which is why this has been tough, but we have had to let them go with that in mind."
However, there is better news for Jean-Yves M'Voto, Francoise Zoko and Irish youngsters Craig Walsh and Gary Shaw, who will all join the npower League One side for a training camp in Leicester.
On Sunderland defender M'Voto, Abbott added: "Jean played really well, particularly in the first half, and he has now gone away to talk to his people and come to a decision on whether or not he would like to talk with us further."