David Luiz shrugged off the recent attention surrounding his Chelsea teammate Diego Costa, telling SFR Sport that "people talk a lot without knowing anything."
Costa marked his return to the side on Sunday with the opening goal in the Blues' 2-0 victory over Hull City, having been left out of Jan. 14's 3-0 win at Leicester City after a training ground row over a back injury, amid links with move to Chinese Super League club Tianjin Quanjian.
The Spain international gave his manager Antonio Conte a warm handshake after being substituted late on in Sunday's win against the Tigers, which sent Chelsea eight points clear at the top of the Premier League.
Luiz, who saw centre-back partner Gary Cahill claim the Blues' other goal, said the speculation around Costa was now just part of the modern game.
"That's his job, to score goals, and he works on that every day," Luiz said. "He does his job very well. He's a great player who's in fantastic form right now. He's playing well, and I'm happy for him because sometimes people talk a lot without knowing anything, and he's had to go through that. But it's normal people talk about the best players in the world, Diego is one of them."
When asked what had happened leading up to Costa's absence against Leicester, Luiz said: "I don't know. Things were normal. Everyone has offers, everyone has things to talk about. He's happy, always wants to play football, that's what's important for me."
Costa's strike against Hull was his 15th goal of the season, and marked his 100th appearance for the club, with whom he remains under contract until 2019.