Real Madrid coach Juande Ramos said he was surprised to learn the club would only be able to register one of its new signings, Klaas Jan Huntelaar and Lassana Diarra, for this season's Champions League.
UEFA rules dictate clubs can register up to three new players for the knockout stage by Feb. 1 but only one who has already played this season in Europe with his previous club.
Netherlands striker Huntelaar and France midfielder Diarra have already played in the UEFA Cup this season for Ajax Amsterdam and Portsmouth respectively.
Asked at a news conference on Saturday if he was surprised when he learned of the rules, Ramos said: "Effectively yes, because I was not aware of it.
"But we still have a month left before we know the ultimate solution," he added.
"We have time and a lot of things can happen. There could be an injury or a player could hit a bad patch of form, and at the moment we are not in the rush to make the decision (on who will be registered)." Real, who face Liverpool in the last 16 of the Champions League, initially said they had a different interpretation of the regulations and would try to register both players but appear now to have accepted only one can take part.