The FA is reviewing an incident where a Newcastle staff member appeared to throw an object towards the Liverpool technical area during the Reds' 2-1 win on Wednesday.
Players and staff from both teams clashed after Fabio Carvalho's 98th-minute winner at Anfield.
It is unclear if the incident, captured on television, sparked the melee in front of the dugouts.
The FA will also consider other factors in the build up to the confrontation.
Boss Eddie Howe called the late winner a "sickener" after his side had led 1-0 through a debut goal from £60m record signing Alexander Isak.
Roberto Firmino equalised for Liverpool before Carvalho hooked in from close range to win the game with almost the last kick.