Diego Simeone says Atletico Madrid are always open to new signings, but an injury to Tiago has increased their need to strengthen in January.
Club president Enrique Cerezo expects the Portuguese to be sidelined for at least three months after he sustained a broken leg in a 1-0 win over Espanyol on Saturday.
"We are always open to any situation when the winter transfer window comes," Simeone said.
"It will not be an exception now, more so due to the absence of a player like Tiago."
A loss of experience in midfield is the coach's main concern, but he is comfortable with the options available in the short term.
"Clearly, it's hard to find another Tiago. At 34 years old there is experience that no-one has at 26 or 27," he said.
"We will work with the guys we have in that position: Koke, Saul, [Matias] Kranevitter, Gabi.
"We will work to see who does better."
"[Winning] the Copa was the beginning of very important things that have happened since," he said, referring to the club's success in the 2012-13 edition of the competition.
"It's not one game, it's two, but we will play with enthusiasm, excitement and great joy."
