Steve Bruce and Matt Ritchie were involved in a sensational training ground showdown in which the Newcastle boss physically confronted the winger and barged into him after being called a 'coward' by the player.
The expletive-laden bust-up — witnessed by stunned team-mates on Tuesday — leaves Bruce's position under threat, with several players no longer trusting the manager, especially after he publicly blamed them for Saturday's 1-1 draw with Wolves.
Ritchie was furious when Bruce, during his post-match interview, accused him of not passing on tactical instructions to the team amid the confusion before Wolves' equalising goal.