The Magpies boss is currently short of striking options following Andy Carroll's deadline-day move to Liverpool last week and Shola Ameobi has since sustained an injury.
Speculation had suggested that Pardew was keen to bring New York Red Bulls forward Henry to St James' Park but he admits the deal could not happen.
When asked about Henry, Pardew told the Evening Chronicle: "I don't think that's possible."
However, he did admit there could be moves in the free transfer market, adding: "I haven't even thought about it, if I'm honest, but we will do over the next 48 hours."
Newcastle ended last week on a high following their remarkable 4-4 draw with Arsenal in the Premier League, despite being 4-0 down at half-time.
But the lack of strikers on the books on Tyneside remains worrying and Pardew could turn to free agents to bolster his squad.
Former Middlesbrough forward Jeremie Aliadiere, with whom he worked briefly at West Ham, is thought to be one of the players under consideration.
Pardew remarked: "There are one or two players we are looking at.
"I don't think we are going to get anyone who could impact on the first team, but on the bench, I need to turn round to that bench and have people who can affect the game.
"We will look, perhaps, to that market for maybe one or maybe two if necessary."
Newcastle's next outing is a trip to Blackburn on Saturday when they will be hoping to build on their weekend heroics.