Hammers manager David Moyes called Masuaku's actions "despicable" and "totally unacceptable" in his post-match press conference, and pledged the player would be firmly dealt with.
The 24-year-old Frenchman reacted to a challenge from Nick Powell at the start of the second half and was sent off.
Arthur Masuaku has apologised for spitting at an opponent. "I've not seen it from him".
"Ultimately, Arthur, what he's done, was despicable", Moyes said. "I've enjoyed him so I'd have to say it is out of character".
One bonus is that West Ham are no longer in any Cup competitions, so will be able to focus on getting their players fit to play in the League matches.
Cleveland Indians will remove 'Chief Wahoo' logo from uniforms in 2019
Dolan's acknowledgement that removing it from the on-field uniform by the start of the 2019 season is the right course". Chief Wahoo signs have also been removed from both in and around Progressive Field .
Sullivan told the fans "We can't sign anyone", and it could be a warning sign that no permanent deal should be expected before Thursday.
"I want to say sorry for my actions on Saturday", Masuaku said in a statement on the club's website.
"It was in the heat of the moment and out of character for me".
West Ham has climbed up to 11th in the Premier League table under the former Everton and Manchester United manager, four points above the relegation zone.
Masuaku took to social media to apologise. "But Its hard to get the right players".
"I think people who know me and know my teams, we'll always engage in a good game whoever we play".