Striker Les and wing-back Christian joined our growing casualty list after picking up injuries at Ipswich Town on Saturday.
Les suffered an ankle problem and was substituted after 28 minutes at Portman Road and a knee injury forced Christian off at half-time.
Boss Glenn Hoddle's initial reaction was to suggest that neither player would be back for two to three weeks.
Both certainly look out of the frame for Wednesday's rescheduled FA Cup third round tie at Coventry City - joining Steffen Freund (knee ligaments) and Teddy Sheringham (suspended) on the sidelines.
Glenn revealed: "Les has got an ankle twist and a kick at the back of the Achilles, so it's quite a nasty one.
"Christian has got a knee problem that will need to be looked at on Monday morning.
"I'm not sure of the timescales yet. Christian might be out a bit longer than Les but that is off the top of my head and until the doctor's had a look and it's been scanned we won't really know.
"We'll keep our fingers crossed it won't be too long but looking at them I can't see either being back for two or three weeks.
"It's a massive blow for us what with losing Steffen Freund as well.
"It's a testing time for the squad because the long-termers are not ready to come back yet."
Les Ferdinand and Christian Ziege could be ruled out of our crucial cup ties against Coventry City and Chelsea.