Chelsea manager Antonio Conte does not know if defender David Luiz has a future at Stamford Bridge.
The 30-year-old was not in Chelsea's matchday squad for the 1-0 win against Manchester United, with Andreas Christensen starting in defence.
Asked about Luiz, Conte said: "He has to work really hard otherwise he is on the bench or in the stand."
On Luiz's future, Conte added: "I don't know. Christensen is the present and the future for Chelsea."
Brazilian Luiz has played the full 90 minutes in each of Chelsea's past three Premier League games, as well as the 3-0 Champions League defeat by Roma in midweek.
But on Sunday he was sitting behind the Chelsea bench, with a black scarf wrapped around his head.
He returned for a second spell with the Blues in a £34m move from Paris St-Germain in August 2016 and was part of the team who won the title last season.
Chelsea's win, courtesy of an Alvaro Morata header, put them a point behind second-placed United in the Premier League table.