"We need some investment in the team and there is no question about that.
"It has been a little bit frustrating, particularly with other clubs around us getting players in. But it is something we are working very hard at and we cannot do things in the rushed fashion we had to earlier in the season."
Palace will be without Aki Riihilahti (calf) again but Joonas Kolkka could return if he passes a late fitness test on a rib injury.