Harold was traded to Philadelphia in exchange for Ryan Bates, Chris Brown of the Bills' official site reports.
General Manager Brandon Beane said Monday that the team sees Harold as a defensive end in a 4-3 set, Chris Brown of the Bills' official site reports.
Harold signed a one-year contract with the Bills on Wednesday, Adam Schefter of ESPN reports.
Harold tallied 10 tackles, four sacks and one pass breakup in 13 games for the Lions in 2018.
Harold logged two tackles, one sack, and one pass breakup during Sunday's loss to the Rams.
Harold (personal) is inactive for Sunday's game versus the Packers.
Harold recorded three tackles, all solo, and two sacks across 21 defensive snaps in Sunday's win over the Patriots.
Harold is active for Sunday's game with New England, Tim Twentyman of the Lions' official site reports.
Harold (hip) is listed as questionable ahead of Sunday's matchup against the Patriots.
The Lions sent the 49ers a 2020 conditional seventh-round pick for Harold (knee), Kyle Meinke of MLive.com reports.