Schefter noted Washington could have fined Haskins up to $14,650 for the violation.
Under the NFL's COVID-19 rules, teams traveling for road games are only allowed a maximum of 70 people in the party, including players, coaches and gameday personnel.
Rules also prohibit any member of the traveling party from leaving their hotel room and no outside visitors are allowed in rooms.
Haskins hasn't played for Washington since Week 4. The Ohio State alum began this season as their starting quarterback, but was benched in favor of Kyle Allen after the team got off to a 1-3 start.
The No. 15 overall pick in the 2019 NFL draft, Haskins has completed 59.6 percent of his attempts for 2,304 yards with 11 touchdowns and 10 interceptions in 13 career games.