Newcastle midfielder Jonjo Shelvey was reportedly angry at being substituted during the side's 0-0 draw with Brighton on Saturday, which led to a dispute with manager Steve Bruce.
With the Magpies second best for long periods of the contest, Shelvey was replaced inside the final 20 minutes by Ki Sung-yueng.
According to The Telegraph, the England international was frustrated by the move, and voiced his displeasure by shouting at Bruce. His manager appeared bemused by the reaction, cupping his hand to his ear to try and hear what the player was complaining about, before shouting a response and shrugging.
The 27-year-old has had a disappointing past 12 months on Tyneside, often finding himself on the bench last season under Rafael Benitez, whilst also dealing with fitness issues. It appeared that he was set to be a regular starter upon Bruce's arrival, having featured heavily throughout pre-season, but he has been left out of the side twice already this season, and being taken off on the weekend was another blow for Shelvey.
With Sean Longstaff closing in on a return, Shelvey's game time could be reduced further in the coming weeks, having failed to impress in the early stages of the campaign.
Newcastle were unable to go on and claim all three points with Shelvey off the pitch on Saturday, meaning that they have five points from their opening six Premier League games. The club are yet to register a home win, and no side has scored fewer goals this season, leaving them just a point outside the bottom three.