Benteke, younger brother of Palace star Christian, made his debut at Middlesbrough last week.
But Pardew told the Croydon Advertiser: "I haven't really been able to judge him yet, if I'm honest.
"He came in to train with us for a week, we were short up front and we stuck him on the bench.
"We put him on and told him to put Middlesbrough under pressure for ten minutes and keep the ball if he could, which he did. I couldn't ask for any more than that. He will get some game time coming up, probably for the U23 development squad.
"We can assess, really, exactly what potential he has. I just haven't really seen enough of him. We were limited in our scouting, but it looks like it's promising at the moment.
"It all came about through his agent, it wasn't Christian. There was a situation that, financially, it made a lot of sense.
"Young strikers are very difficult to get hold of in this market, so it was a no-brainer really."