West Brom fear reigning player of the season Youssouf Mulumbu faces an extended lay-off with a troublesome groin injury.
Mulumbu, 24, limped off towards the end of the Baggies' hard-fought goalless draw against Premier League leaders Manchester City on Boxing Day.
Boss Roy Hodgson admitted after the Hawthorns clash that the injury has been a long-standing problem for the Congo international.
And he is worried the midfielder has aggravated it further by not coming off the pitch earlier.
"He's had a groin strain for a while now so we will have to have a look at it," said Hodgson. "I'm hoping it's not going to be too bad.
"I think it's something that will keep him out for a little while but let's hope it's not too long because he has got himself back in form.
"He's been suffering from a groin injury that we've been nursing him through game to game and it's gone fine.
"His last 10 minutes was 10 minutes too many and if I'd have had some indication he was struggling I'd have taken him off.
"But unfortunately there was no indication or any suggestion he was being hampered by it and as a result it's turned into perhaps a slightly more serious injury."