Ahead of Sunday's trip to former club Southampton, the Magpies boss sees his side sat 14th in the Premier League after back-to-back defeats by West Ham United and Swansea City.
Newcastle, after finishing fifth last season, had ambitious plans of qualifying for the UEFA Champions League in the current campaign but they have been hampered by squad problems.
Yohan Cabaye is having groin surgery, captain Fabricio Coloccini is suspended and Ryan Taylor, Dan Gosling and Haris Vuckic are all injured and the Senegalese Football Association blocked Papiss Cisse from playing against Swansea.
And Pardew may use the winter transfer window to find reinforcements, as he said: "If we get to January and we're in a vulnerable position, where we are now or lower, then we're going to need to have a little bit more thought about how we're going to go forward.
"We're talking about West Ham putting a big puncture in our season. If we'd have won that game, we'd have been in the top six.
"Then we had massive blows before Swansea with Papiss Cisse being withdrawn and Yohan Cabaye's injury. I'm not going to get too down about it at the minute.
"I still believe in this side. I still believe it's a very good side when I put it out there. But the guys who are in and around the squad need to step up now and prove they're good enough."