Costa left Chelsea in September following a breakdown in relations with head coach Antonio Conte and returned to Atleti, having departed to join the Premier League champions in 2014.
The Spain international is not eligible to make his second Atletico debut until January and Simeone has opted to avoid the potential distraction of Costa returning to his old stomping ground.
Asked why the 29-year-old had not travelled to the London, Simeone told a pre-match news conference: "Because I am the manager. I made the best decision what I think was best for the team.
"I don't think we need to think about that too much. We need to think about our game tomorrow."
Costa was in the stands at the Wanda Metropolitano when Chelsea claimed a brilliant 2-1 away win in the immediate aftermath of his transfer being finalised.
Atletico remained winless in Group C until a spectacular volley from Antoine Griezmann and Kevin Gameiro's late second saw them beat Roma 2-0 last time out.
To progress, the 2014 and 2016 finalists must beat Chelsea and hope Qarabag are able to draw against Roma – a feat they managed twice versus Simeone's men.
"We don't have to be looking about what happens in Rome," the Argentinian added. "We just have to think about us.
"It's not going to be a simple game. We need to take the game to where we feel we can hurt Chelsea.
"It's a personal challenge to fight for everything we've worked for these last few years."
One ex-Chelsea man who is set to be involved on Tuesday is Filipe Luis and the left-back told reporters there is something of the caged animal about the match's most noted non-participant at present.
"Diego is a huge player. He is the best for me because he scores a lot of goals and important goals," he said.
"I think he came back to Atletico because it was his desire. He was happy here. He did his job really well. His most important desire was to come back.
"It is frustrating seeing him playing [in training] like an animal, but he can't play. It's just a month until he can play with us. He'll help us a lot. I don't have any doubts about it.
"He knows the club, he knows the way we play. He has already adapted. I know it was difficult times for him and for Chelsea. Now everybody's happy. We want to see him play and happy again."