Simeone spoke of Modric and Real goalkeeper Thibaut Courtois ahead of today's derby.
"Luka Modric is their most decisive player," he said at his pre-match press conference on Friday.
"That remains the case."
Courtos is not exactly a favourite among supporters of Los Rojiblancos, but Simeone remains grateful for what the Belgian did at the club.
"I cannot put myself in the position of those people to understand the feelings they have," he said.
"He's a great goalkeeper who did well for us and now he's enjoying a great time in his career."