Chelsea have told Diego Costa to show more respect toward manager Antonio Conte, according to multiple reports in English newspapers.
Costa opened the scoring in Saturday's 3-0 win against Leicester but grew agitated during Conte's second-half substitutions and gesticulated angrily toward the Chelsea bench on several occasions.
His actions gave rise to suggestions that he might be concerned about the possibility of picking up an injury or fifth booking of the season that would rule him out of next weekend's clash with Manchester United.
But reports in Tuesday's newspapers, published online at the same time on Monday night, say Costa was asking to come off because he no longer wanted to listen to Conte's instructions.
The Telegraph reported that Costa "had become annoyed by Conte's hands-on coaching style" from the touchline, while The Mirror said the striker was "furious at what he saw as Conte's criticism of his performance."
Costa believed Conte "should take him off if he was not good enough," according to the Daily Mail.
In his postgame comments, Conte played down any rift with the Spain international, saying "I decide the substitutions" and "Costa's passion is important for the team."
But according to the reports, Costa's gestures did not sit well with some within the club, and the 28-year-old has been warned over his future conduct.
Costa also clashed last season with former Chelsea manager Jose Mourinho, who dropped the forward following a public spat during a Champions League game away to Maccabi Tel Aviv.
Mourinho did not select Costa for subsequent Premier League matches against Tottenham and Bournemouth, and Costa threw his bib in Mourinho's direction after he was dropped at White Hart Lane.
The current Manchester United boss then sent Costa out to warm up during the second half before telling him to sit back down with the rest of the substitutes.