Crystal Palace chairman Steve Parish reportedly addressed the players after the side's 4-0 humiliation at home to relegation rivals Sunderland on Saturday.
According to The Guardian, Parish had the blessing of Eagles manager Sam Allardyce to directly speak to the squad with "an impassioned speech" in which he "made clear their performances of late, a win at Bournemouth aside, have been unacceptable".
Allardyce then had the players report to their training ground at 7am on Sunday in order to "pick apart" their poor defensive display against David Moyes's side.
The home support were audibly upset during the clash at Selhurst Park, with chants of "you're not fit to wear the shirt" echoing around the ground as the half-time whistle blew, while one angry fan was arrested after making it onto the pitch to confront Damien Delaney.
Palace - the biggest spenders in the January transfer market with the £30m captures of Jeffrey Schlupp, Patrick van Aanholt and Luka Milivojevic - are currently 19th in the Premier League and two points from safety ahead of a trip to Stoke City this weekend.