The Hoops have already brought in Alistair Johnston, Yuki Kobayashi, Tomoki Iwata and Oh Hyeon-gyu during the window and Postecoglou admitted that there will no further new additions ahead of Tuesday’s midnight deadline.
Any movement will take place in the opposite direction with talks continuing over a potential move out of Glasgow for Greece striker Giorgos Giakoumakis, who looks set to have his move to MLS side Atlanta United confirmed "within the next 24 hours”.
“There won’t be any other incomings,” Postecoglou said. “In terms of outgoings there are still some things happening in the background but nothing confirmed yet.”
On Giakoumakis, he added: “We are getting to the tail end of it one way or another and we will get a conclusion in the next 24 hours. Nothing concluded yet, just ongoing discussions.”
The likes of Yosuke Ideguchi and Oliver Abildgaard could move on, while Sheffield Wednesday have been credited with an interest in defender Stephen Welsh.
The Celtic manager added: “We have already brought in players to insulate us if guys who have not played a lot of football for us find other opportunities. It has to suit all parties obviously. We will see what happens over the next few hours.
“Anyone who is playing football and has been a meaningful contributor won’t be leaving in this window. Potentially the ones who leave are ones who haven’t had a lot of regular game time. There are four or five in the squad, I am not going to talk about individuals.”