Nacer Chadli has been ruled out for two months after suffering a recurrence of a thigh injury, West Brom boss Alan Pardew has confirmed.
Chadli made his return from injury against Stoke City on Saturday but lasted only 15 minutes before succumbing to injury again.
And Pardew, whose side take on Arsenal in the Premier League on Sunday, said Belgium international Chadli is set for another lengthy spell on the sidelines.
"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. "I said coming out of the Stoke game that it was probably a bigger blow than the result.
"That's something we're going to have to deal with and it's something that I'm going to have to look at in January because it's a quality player going out of the group for some considerable time.
"On the medical side of that issue they ticked all the boxes and more. We're just a little bit unfortunate that it reoccurred and that can happen. 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.
"Not only does he want to do well for the club, for me and for the fans but he also has the World Cup around the corner. He's really disappointed and upset but he'll be okay. He'll get his head around it. He's experienced enough to do that."
AP: "The front three of @Arsenal is world class. Any national team would be happy with that front three. Every game gets more and more important. Our fans were brilliant against @Everton and if they're the same against @Arsenal I'll be overjoyed."#WBA-- West Bromwich Albion (@WBA) December 29, 2017
West Brom have only scored two goals in six Premier League matches since Pardew was appointed as the successor to Tony Pulis.
But the Baggies have been boosted by the news Salomon Rondon's hamstring injury is not as bad as first feared - the striker having hobbled off after missing a great chance against Everton on Boxing Day.
"Just Salomon is a doubt from the squad that I had the other day," Pardew added.
"He came off with that tweak to his hamstring but I can report that it's not serious. I think the next two games he's probably a doubt but after that it should be fine. It's not a long-term problem which is very useful in where we are at the moment.
"James [Morrison] is getting closer, he's starting to jog around. I suffered a really bad Achilles injury as a player and they're temperamental.
"You think you've got it but then it fattens up again and you can't get that unrestricted movement you need in that area. He has to be patient but I know he's desperate to come back."