The Spaniard has joined his boyhood club on loan until the end of the 2015-16 campaign from Milan.
Torres, 30, has made 10 appearances in the Serie A this season – and that, along with training, is enough for him to start at the Vicente Calderon.
"Fernando Torres has been training and playing for Milan. He played, if I am not mistaken, 10 matches there," Atletico coach Diego Simeone told a media conference on Tuesday.
"He has been training with us for a few days, so tomorrow he is going to start in the team, I hope he has a great match and helps us find what we need to move forward."
Simeone is wary of Real can produce, despite Carlo Ancelotti's men seeing their 22-match winning run come to an end with a loss to Valencia on Sunday.
He rubbished suggestions his team's city rivals were unfit after the mid-season La Liga break.
"I have been watching Real Madrid a lot and they don't lack fitness. The other day they played an intense match against Valencia. They have just won the Club World Cup," Simeone said.
"I always expect a great match because they have great players, who won many matches before. They have an awesome coach and I am expecting to face a very strong team."
