The Spanish right-back has been out of action since the 3-1 Champions League victory over Borussia Dortmund on 26 September after being diagnosed with pericarditis.
But the Spanish international has stepped up his recovery during the international break and will be available for the crucial derby.
Asked by OK Diario whether he will have any problem to be ready to feature again against Atletico on Satuday, Carvajal said: "No, In principle I already have my medical discharge to start playing again, without any kind of problem. I don't think that anything will happen to me.
"I would have liked to return sooner, but in the end we reached an agreement to do so after this international break. That would serve to bring me back into the rhythm of playing competitively so that I'm able to face the whole month-and-a-half before Christmas.
"I have trained a lot, aside from with the ball, adding to the sessions I have done in the gym and with the rest of the team. It has practically been like a mini pre-season."
However, Zidane may delay his return to the starting line-up after having previously admitted that he won't take any risk with Carvajal due to the seriousness of the issue.
"I was scared and I thought that, if it was serious, I would have to retire," Carvajal said. "The first three or four weeks were the worst because I practically couldn't do anything, I couldn't raise my heart rate in any way and it was very low."
Meanwhile, Zidane received more positive news during the Wednesday's workout with Isco and Mateo Kovacic returning to training.
Isco had to pull out of the Spain squad over weekend after being forced off during the 5-0 victory over Costa Rica following a heavy challenge by Kendall Watson.
The 25-year-old midfielder consequently missed the 3-3 draw with Russia on Tuesday [14 November] night but could be back to help Real at the New Wanda Metropolitano this weekend.
Kovacic, meanwhile, has not played since suffering an adductor muscle injury in his right leg during the Champions League win over Apoel Nicosia on 13 September.
The Croatian international was able to participate in the first part of the workout with the rest of his teammates but it is still uncertain whether he will be 100% fit to face Atletico.
Furthermore, his compatriot Luka Modric also was back in training after helping his national team to book a place in the World Cup 2018.
"Third training session of the week at Real Madrid City as the team continues to prepare for the derby at the Wanda Metropolitano (Saturday, 8:45pm CET). Zidane saw three players return for the session. Isco and Modric, who worked individually on Tuesday, joined the group. Kovacic also trained for the first time with his teammates since his injury. The Croatian started with the group and ended up doing more work alone out on the grass," the club confirmed.
However, it looks like the Madrid derby will come too early for Gareth Bale, Luca Zidane and Keylor Navas who are yet to re-join the group.
"Bale, Luca and Keylor Navas continue with their respective recovery processes. The Costa Rican goalkeeper was out on the field training alone," Real Madrid added.