Real Madrid are short of strikers and Gonzalo Higuain's back problem could make it tough to get through the coming weeks with only Karim Benzema as an out-and-out attacker, coach Jose Mourinho said on Saturday.
Argentina international Higuain, who has been first choice ahead of Benzema under Mourinho, may need an operation that club doctors say would sideline him for around two months.
The injury has prompted speculation in local media that the big-spending La Liga giants could buy another striker in the January transfer window but Mourinho stopped short of making a plea for reinforcements.
"Signing players is not an issue for me to deal with but I already said at the beginning of the season it would be difficult with only Benzema and Higuain," Portuguese Mourinho told a news conference.
"If I have to go through the rest of the season only with Benzema it will be much more difficult," he added.
"But this is something you have to ask the director general (Jorge Valdano) and he can tell you the club's position."
Mourinho said he expected Kaka to return in January after "spectacular" work from the Brazilian in his recovery from a knee operation that has prevented him playing this season.
"(There has been) good work from the medical department ... spectacular work from Kaka himself, which is the most important.
"We are waiting and I think that when we come back from Christmas I hope to have Kaka training with the team again."
Real, who are safely through to the last 16 of the Champions League, play at Real Zaragoza in La Liga on Sunday.