The NHL announced Hathaway's suspension Wednesday after a hearing with him. He will forfeit $24,194 in salary.
Toward the end of a heated brawl between the Capitals and Ducks on Monday night, Hathaway responded to a rabbit punch from Erik Gudbranson by spitting on the Anaheim defenseman. Hathaway was ejected with a match penalty that carried with it an automatic suspension pending review by the league.
The 27-year-old has been a strong addition to the Capitals, who signed him in July. With Washington in salary cap trouble because of injuries and the suspension, the team put winger Carl Hagelin on long-term injured reserve and Nic Dowd on injured reserve and recalled two minor league forwards to play Wednesday night at New York.