The 20-year-old Portugal forward missed six matches after suffering right ankle ligament damage during last month's 1-1 draw against Valencia.
Club-record signing Joao Felix's return comes as a boost to head coach Diego Simeone, who learned this week he will be without Diego Costa until the new year.
The former Chelsea striker underwent neck surgery on a herniated disk and, although Joao Felix adds welcome creativity to the Atleti attack, Simeone pointed out he cannot directly solve his Costa problem.
"No, he is not a forward in that sector," Simeone told a news conference, before informing reporters youngsters Ivan Saponjic and Dario Poveda would be providing cover for first-choice striker Alvaro Morata.
"With Saponjic, we have been telling him what he needs to get close to being able to compete with us."
Atleti president Enrique Cerezo said before Costa's operation there were no plans to bring in another striker in January and Simeone is seemingly content to work with what he has, while acknowledging Atleti might look to capitalise upon any opportunities thrown up when the market opens.
"I think about reality and that is that we have Alvaro, Dario and that we have to improve Ivan," he said.
"We trust Dario who can use that space to grow, he is only 20 years old , good height, good in the air.
"Both in the winter and summer markets you always have to be open to everything because everything can happen. The representatives do their job well and maybe there can always be some player who wants to go, another one who wants to come.
"In the middle of the season, the loss of Costa is important for his personality and what he conveyed in the locker room.
"He was not at his best, but he was there. His place will be covered by Dario, [Rodrigo] Riquelme and Saponjic if he manages to approach what we need."
Third-placed Atletico are a point behind Barcelona and Real Madrid in LaLiga, having played a game more than the leaders, and Simeone also has selection concerns in midfield.
Saul Niguez and Thomas Partey will both sit out the trip to Los Carmenes due to already amassing five LaLiga yellow cards this season.
"Both Thomas and Saul are out and give way to Marcos Llorente and Hector Herrera, to follow the line that the team has been taking," Simeone added, before noting the match as a particular opportunity for Llorente, a close-season acquisition from Real Madrid.
"For Marcos it is an important game. He is not having the chance to play because the Thomas, Saul and Koke are doing very well.
"He has worked very well and for sure he will play a game as a result of how he has worked."