The Press Association understands the breach relates to an unauthorised absence from training.

The 31-year-old also missed Saturday’s 2-0 loss to Arsenal, but that was put down to illness.

Grealish, who is on a second consecutive season-long loan from Manchester City, had started Everton’s previous three Premier League matches against Ipswich, Hull and Chelsea, and has made a total of six appearances for the Toffees this term.

Last season, Grealish provided six assists and added two goals in 20 appearances before suffering a season-ending foot injury in January.

Having enjoyed his time on Merseyside, Grealish remained with Everton during his rehabilitation.

A player who cost City £100million in 2021 began this season as part of Enzo Maresca’s squad at the Etihad Stadium, featuring as a substitute in both their 3-0 Community Shield loss to Arsenal and their Premier League opener against Bournemouth, a 2-1 win.

He returned to Everton on loan on September 1.

Everton are hosting Newcastle for a place in the quarter-finals, where Fleetwood await after their shock victory over Premier League champions Arsenal on Tuesday night.