Foster expects reinforcements next month but says any new players must be up for an intense relegation battle.
He said: “Getting in the right sort of players – that's the important thing.
“Players who want to fight, who need to fight – almost like they've got a point to prove.
“There's no point splashing out money on players who are going to be lovely on the eye. We need them to dig in.
“Because otherwise when the chips are down they are not going to be there to help you out.
“Come prepared for a scrap, without a doubt, yes."