Ex-Brazil international Lucio has little doubt Oscar still has a role to play at Chelsea and has backed his compatriot to become a key figure for the Premier League champions again.
The 24-year-old joined Chelsea from Internacional in July 2012 and quickly became an important first-team member at Stamford Bridge.
"Oscar plays an attacking and skilful game with the national side. At Chelsea, he plays a different role. It is two different styles of play and he needs to adapt," Lucio told IBTimes UK.
"There will be a period where Mourinho's style may not suit him, but he has to adjust and adapt. Once he does it, he will be a top player, a very good player.
"His dip in form is just a question of adapting. He should work hard in order to improve his game and be a big player at Chelsea."
