Chelsea’s players have been told that no-one’s place is safe if the club’s poor start to the season continues.
Manager Jose Mourinho has left John Terry out for the past two Premier League games, while Branislav Ivanovic and Cesc Fabregas have been criticised.
“Untouchables in football – only consistency can give you that status,” said Mourinho, whose side are 14th in the table after seven games.
“Football is about today. At this moment I don’t have untouchables.”
Terry, 34, has started only the League Cup win at Walsall since a 3-1 defeat at Everton on 12 September.
Champions Chelsea, eight points behind leaders Manchester United in the league, travel to Mourinho’s former club Porto in the Champions League on Tuesday.
In 2006, during his first spell in charge, Mourinho described eight of his first-team players – including Terry, Ashley Cole, Frank Lampard and Didier Drogba – “untouchable” because of their form.
“In this moment we have fantastic players, the players that gave us the title last season,” Mourinho said.
“But football is not about yesterday. In football you have to be consistent in your performance, in your emotion.
“To be a winner you don’t need to win all the time, but to be a winner you must have a strong mentality every game, every day.”
Mourinho will have striker Diego Costa available in Porto as his three-match ban does not apply to European games.
Asked if he needed 11 Costas on the pitch, Mourinho said: “We would lose every game, because the desire to suspend him is so big that we wouldn’t have players to start the game.
“I’m happy to have only one and let him play until they decide to suspend him again.”
Goalkeeper Iker Casillas, who Mourinho dropped while in charge of Real Madrid, is part of the Porto side.
Mourinho interrupted the first question on the subject in the pre-match news conference.
“If you’re going to ask me about Casillas, I’m going to greet him at the beginning and the end. No more questions about it,” he said.