Luiz has been in and out of the starting line-up this season, with Mourinho shuffling his pack in central defence with the Brazilian battling John Terry and Gary Cahill for a spot in the first XI.
Brazil international Luiz was left out of Chelsea's last two games against Schalke and West Brom after starting the 2-0 defeat to Newcastle at the start of the month.
However, Luiz is not concerned about losing his spot in Mourinho's side and will continue to work hard to force his way back into his plans.
"It will be like it has always been, I am never worried," Luiz told UOL. "I train hard and seriously every day, he has his options."
Brazil manager Luiz Felipe Scolari has refused to get involved in any issues with Mourinho over his decision not to play Luiz.
"It depends on the managers and the clubs where they play if the players will be starters," said Scolari.
"When I call up someone for the national team, I do so based on my observations. I won't interfere in their job because I don't want any of them to interfere in my call ups."