Tottenham manager Antonio Conte has admitted Son Heung-min is no longer undroppable.
Conte has previously that he would be 'crazy' to drop the South Korean forward.
But Son has started the season without scoring a single goal, and Conte has fired a warning to his star player.
Speaking on Monday ahead of Tuesday night's clash against Sporting, Conte said: "I think when you try to build something important, when you try to build something with ambition and try to be competitive and fight to win, you have to change old habits, otherwise it means you want to stay in balance and it means you don't want to have ambition.
"For this reason all the players have to accept the rotation especially up front, we have four players. For me especially it's very difficult right now to drop one of these four players, but I have to make the best decision for the team, also for the players.
"Sometimes it's better to rest and don't start a game, to come in and play only 20 or 30 minutes and then play the following games.
"For sure I'm here to try to change the old habit. The old habit was that the players were used to playing in every game. What happened in this type of situation is that you don't have great possibilities to win.
"You try to make the players happy, but big clubs have a big squad, a deep squad. In this moment we don't have a big squad but we have just started to try to follow this path.
"For this reason what happens with one of these four players will be normal and you have to know it's good for a coach like me to have these options."
