"I'd expect to have at least two players, maybe three, before the window closes," Calderwood said.
"We are just fine-tuning things at the moment regarding which positions we want to fill.
"There are choices to be made about whether we move for two defenders or one defender and an attacking player or more.
"Quido Lanzaat is still in our thoughts. He did really well during his trial last week and is available on loan from CSKA Sofia.
"He is a good footballer and didn't do himself any harm, but it depends which way we want to go. But no transfer fees will be involved. It will be loans only."