Chadli made his return from injury against Stoke City on Saturday but lasted only 15 minutes before succumbing to injury again.
The defensive midfielder's time in the Premier League hasn't exactly been a success, with West Brom yet to win a game he has participated in, which doesn't help the French club's situation.
"Nacer looks like his injury is as bad as it was originally so we think he's going to miss the first two months of this year which is a big blow to us", Pardew said on Friday. "It's hard to predict what is going to happen in the game, but what I can say is that we will do everything we can to get the three points in front of our fans". Next time round we're going to have to be even more careful and cagey around it - that's why I'm saying two months, rather than possibly less which it could be.
Pardew's side sit second bottom of the Premier League and have managed just 14 goals in the campaign so far, and the West Brom boss is looking to a direct approach to tackle an in-form Arsenal side.
"On the medical side of that issue, they ticked all the boxes and more, we were just a little bit unfortunate it reoccurred and that can happen".
"Not only does he want to do well for the club, me and the fans, but he also has the World Cup around the corner. He's experienced enough to do that".
AP: "The front three of @Arsenal is world class".
The east London outfit have undoubtedly improved since the 54-year-old took over, but there have been signs of their old habits creeping back into their game over the last two matches against Newcastle United and Bournemouth respectively. It's not a long-term problem which is very useful in where we are at the moment.
"I do see improvements under Pardew, he's playing the ball forward more, but they haven't got a goalscorer!"