The 71-year-old, who is the most successful manager in the history of MLS after winning spells at D.C. United and LA Galaxy, will not be returning to the Revs dugout anytime soon.
In an official statement on their website, the club commented: "The organization takes any allegations of workplace misconduct extremely seriously and is working closely with the league and fully cooperating with its investigation."
It's reported in The Athletic that no timeframe has been placed on Arena's absence as the external investigation into his comments continues.
Arena is a massive name in American football after managing the USMNT at both 2002 and 2006 World Cups and would have had a third go in 2018 if he wasn't relieved of his duties halfway through the qualification campaign.
The New England Revolution players have been told Arena won't be involved whatsoever while the investigation goes on, with technical director Curt Onalfo and assistant coach Richie Williams taking charge for the time being.
The Revs are next in action on August 10 as they take on Liga MX side Atlas in the Round of 32 stage of the Leagues Cup.