Atletico Madrid president Enrique Cerezo expects Tiago to be out for at least three months after suffering a broken leg.
Tiago was replaced by Yannick Ferreira Carrasco in the 33rd minute of Atletico's 1-0 win over Espanyol, with a subsequent scan revealing the extent of his injury.
Cerezo was joined by a group of players in visiting the Portuguese at hospital while he awaits surgery on Sunday.
However, the president hopes Tiago can return before the end of the season.
"In spite of the injury he's fine and keeping his spirits up. I think he'll be out for three months," Cerezo said.
"He has a fractured tibia and will undergo surgery. It's a very important loss for us but we hope he returns soon and can be back playing.
"All we are thinking about at the moment is Tiago and hoping that his operation turns out successfully."
Diego Simeone lamented the loss of the former Chelsea midfielder and wished him a speedy recovery.
"Tiago is out injured, but with every day that passes he is closer to being back with us," he said.
"He's a player with a tremendous amount of energy, he'll be back in good time.
"I'd like to send him all of our energy – from the club, the fans, the squad. We love him very much."
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