All four players are out of contract at the start of next month and are discussing their futures with the club.
However, there will be notable departures with Darren Ambrose, Svetoslav Todorov and Nicky Weaver being released along with Aswad Thomas and Rashid Yussuff.
Chairman Richard Murray told the club's website: "In light of the club's financial situation we have to talk and discuss the future with every out-of-contract player and their agents and there are quite a few in this category this summer. Of course, at the same time they have every right to talk to other clubs as well.
"We have made a number of firm decisions but are also having talks, which are ongoing, with Jonathan, Matt, Darren and ZiZi.
"What's more, while that process continues, the coaching staff and scouting team are identifying players we may want to bring to the club and we are also talking to a number of other clubs, players and their agents."