Cardiff City midfielder Stephen McPhail could be out for a few weeks with a recurrence of Sjogren's Syndrome which he has suffered from in recent months.
McPhail, who is in remission from a stage one lymphoma, will be missing for Cardiff City's Championship clash at Millwall.
"It's flared up at the moment so it's something we will monitor closely," said Cardiff City manager Malky Mackay.
"We have got to be very careful of how we deal with it."
Added Mackay: "The medical department are right on top of it. We will give him every back up we can hoping that in a couple of weeks' time that settles down and he's back to where he was a few weeks ago.
"I can't put a time on it but I would hope in we would have him back in a couple of weeks.
"He's a fine man. He's someone I've got an awful lot of time for. Great mental strength in terms of what he has been through."
Also out is defender Anthony Gerrard who misses the trip to London with a hamstring injury.
Gerrard was injured in the victory over Birmingham as the Bluebirds went third in the Championship.
But though Gerrard is sidelined midfielders Filip Kiss and Aron Gunnersson look likely to travel to London with the team.
Kiss (ankle) and Gunnarsson (dead leg) were also injured during the win over Birmingham City on Sunday.
McPhail has endured a difficult two years after being diagnosed with stage one MALT lymphoma in November 2009.
The 31-year-old, who has made more than 150 appearances for the Bluebirds, had cancer treatment after a lump was removed from his neck.
And his preparations for the 2011/2012 season were disrupted when he was originally struck down by the Syndrome.