Harry Redknapp admits Luka Modric is a ‘big doubt' ahead of Tuesday night's Champions League group stage match with Werder Bremen.
The Croatian midfielder injured his left leg in Saturday's 1-1 draw at West Brom, forcing him to limp off at the Hawthorns.
And although X-rays have revealed no serious damage, the manager is cautious in taking any risks with the player in Germany and will leave it to Luka himself to decide whether he is ready for match action so early after picking up the injury.
Harry said: "The only big doubt we've got is Luka. He's very doubtful. He travelled with us and we're going to have a look at him.
"The news was good on the scan because there was nothing broken, but there's still pain in his leg so we're going to have to see how he is.
"Only he can decide. We were fearing the worst news [before the X-ray] and it looked as though he'd got a break again having had a similar type of injury last season.
"I couldn't take a chance on him unless he feels right. I can't have him going out there, breaking down and getting injured for the long term.
"He's a great professional and wants to play all the time, but he'll tell me how he feels and I must say he's very doubtful."
There are also question marks over the fitness of new signings William Gallas and Rafael van der Vaart, who both played 90 minutes on their debuts in the Midlands on Saturday.
Harry continued: "They did well but that was their first game having not played at all, so I will have to see what affect that game had on them before I make a decision as to whether they play or not.
"That was Rafael's first 90 minutes since before the World Cup, and William's first 90 minutes since the World Cup.
"They were both completely wiped out at the end of the game on Saturday. It was tough for them so I'll have to see how they feel and take it from there.
"But they were both excellent and they've got experience having been there and done it all, and that experience would be important. It's whether I feel they're ready to play again so quickly."
Heurelho Gomes (groin) and David Bentley (ankle) are not yet fit enough to have made the trip, joining longer-term absentees Jermain Defoe, Michael Dawson, Jamie O'Hara and Jonathan Woodgate on the sidelines.