The Senegalese forward was left out of the starting line-up for their last league match against Everton before coming off the bench at half-time to grab both goals.
However, there has been tension behind the scenes in recent times, with the striker reportedly frustrated with his role at the club, and Pardew has confessed that the release clause that was previously assumed to have expired in the summer is still active.
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"There is that clause in his contract and it makes us vulnerable," Pardew told reporters.
"It's still open in the next window."
The 27-year-old finished as the club's top goalscorer last season with 16 goals and Pardew has revealed that he has since spoken with the player after comments released from his agent hinted at his unhappiness and willingness to seek a move away from Sports Direct Arena unless things changed.
"I have spoken to Demba [about his agent] and told him I was disappointed with some of the comments around him," Pardew explained.
"Sometimes it's out of his control and out of my control.
"But we know each other well enough, and I've got no problems with him, because he is a team player who wants to do his best for the team. He has always been like that."I just think the agent stuff was people saying things they shouldn't say, really. It doesn't really affect myself and Demba, because we've got a very good relationship."