Per the NFL: 49ers linebacker Dre Greenlaw has been suspended without pay for one game for an act of unsportsmanlike conduct during Sunday’s game against the Seattle Seahawks.   During the second quarter, Greenlaw used his helmet to headbutt Seattle linebacker Ernest Jones IV, who was not wearing a helmet, violating Rule 12, Section 3, Article 1, which applies to “any act which is contrary to the generally understood principles of sportsmanship.”   Greenlaw will be eligible to return to the 49ers’ active roster on Tuesday, October 20, following the team’s October 19 game against the Washington Commanders.   Under the Collective Bargaining Agreement, Greenlaw may appeal the suspension. Any appeal will be heard and decided upon by either Derrick Brooks, Jordy Nelson, Ron Rivera, or James Thrash, the hearing officers jointly appointed and compensated by the NFL and NFLPA to decide appeals of on-field player discipline.